How does the stored XSS vulnerability work?

The vulnerability arises from insufficient input sanitization and output escaping in the plugin’s block rendering logic. An attacker with contributor-level access can craft a post or page containing the Liquid Speech Balloon block and inject a malicious script into a block attribute, such as the balloon text or name field. When an administrator or other user views the published content, the script executes in their browser.

Who is affected by this vulnerability?

Any WordPress site running LIQUID SPEECH BALLOON version 1.2.5 or earlier is affected. The attack requires an authenticated user with at least contributor-level access, so sites with multiple authors or contributors are at higher risk. Administrators and other users who view pages containing the malicious block are the ones whose sessions could be compromised.

How can I check if my site is vulnerable?

Check the installed version of the LIQUID SPEECH BALLOON plugin in your WordPress admin dashboard under Plugins. If the version is 1.2.5 or lower, your site is vulnerable. Additionally, review any pages or posts that use the Liquid Speech Balloon block for suspicious content, especially those authored by users with contributor-level access.

How does the proof of concept (PoC) demonstrate the issue?

The PoC typically involves an attacker with contributor-level access creating a post with the Liquid Speech Balloon block and inserting a JavaScript payload into a block attribute, such as the balloon text. When an administrator previews or publishes the post, the script executes, demonstrating the stored XSS. This confirms that the plugin fails to sanitize output properly.

What is the root cause of the vulnerability?

The root cause is the lack of proper input sanitization and output escaping in the plugin’s block rendering logic. The block attributes are not sanitized when output, allowing malicious scripts to be stored and executed. The provided patch does not directly address this, but the version bump to 1.2.6 indicates a fix was released elsewhere.

How has the vendor patched the vulnerability?

The vendor released version 1.2.6 to address the vulnerability. Although the provided code diff mainly updates script dependencies and admin notice transients, the actual fix likely involves adding sanitization functions like esc_html() or wp_kses() to the block attributes during rendering. It is crucial to update to version 1.2.6 or later to mitigate the issue.

What steps should I take to fix or mitigate the issue?

Immediately update the LIQUID SPEECH BALLOON plugin to version 1.2.6 or later. If you cannot update, consider disabling the plugin temporarily or restricting contributor-level access. Additionally, audit existing content for any injected scripts and remove them. After updating, verify that the block renders correctly and no malicious code remains.

Can this vulnerability be exploited by unauthenticated users?

No, the vulnerability requires an authenticated user with at least contributor-level access. Unauthenticated users cannot directly exploit it. However, if a contributor account is compromised, the attacker could leverage this vulnerability to escalate privileges or perform other malicious actions.

Are there any other versions affected?

The vulnerability affects all versions up to and including 1.2.5. Version 1.2.6 is the patched version. If you are using an earlier version, you should upgrade to 1.2.6 or later to ensure your site is protected.

What should I do if I suspect my site has been compromised?

If you suspect exploitation, immediately update the plugin to the patched version, scan your site for malicious code, and review user accounts for unauthorized changes. Change all passwords, especially for administrator accounts, and consider using a security plugin to monitor for further attacks. Also, check server logs for unusual activity.

Published : August 11, 2026

CVE-2026-65527: LIQUID SPEECH BALLOON <= 1.2.5 Authenticated (Contributor+) Stored Cross-Site Scripting PoC, Patch Analysis & Rule

Q: What is CVE-2026-65527?

CVE-2026-65527 is a stored cross-site scripting (XSS) vulnerability in the LIQUID SPEECH BALLOON WordPress plugin, affecting versions up to and including 1.2.5. It allows authenticated users with contributor-level access or higher to inject arbitrary web scripts that execute when other users view the affected page. The vulnerability has a CVSS score of 6.4 and is categorized under CWE-79.

Q: What is the practical risk of this vulnerability?

The CVSS score of 6.4 indicates a medium severity. Exploitation can lead to session hijacking, forced administrative actions, website defacement, or distribution of malware. Because the script is stored in the database, the attack persists and affects any user who views the compromised page, making it a significant risk for sites with multiple users.

CVE ID CVE-2026-65527

Plugin liquid-speech-balloon

Severity Medium (CVSS 6.4)

CWE 79

Vulnerable Version 1.2.5

Patched Version 1.2.6

Disclosed July 22, 2026

Analysis Overview

Atomic Edge analysis of CVE-2026-65527: The LIQUID SPEECH BALLOON WordPress plugin, version 1.2.5 and earlier, contains a stored cross-site scripting (XSS) vulnerability. This vulnerability allows authenticated users with contributor-level access or higher to inject arbitrary web scripts. The scripts execute whenever a user accesses an affected page. The vulnerability carries a CVSS score of 6.4 and is categorized under CWE-79 (Cross-Site Scripting).

Root Cause: The root cause lies in insufficient input sanitization and output escaping. The vulnerable code path is within the plugin’s block rendering logic. Although the specific diff does not show the vulnerable sanitization code, the issue stems from the block attributes not being properly sanitized on output. The `liquid_speech_balloon_editor_assets` function enqueues the block script (`lib/block.js`), which is responsible for frontend rendering and is vulnerable to script injection via unsanitized block attributes.

Exploitation: An attacker with contributor-level access exploits this by crafting a post or page containing the Liquid Speech Balloon block. The attacker injects a malicious XSS payload into a block attribute, such as the balloon text or name field. When an administrator or other user views the published content, the injected JavaScript executes in their browser session. This attack vector uses the standard WordPress block editor interface and does not require special endpoints.

Patch Analysis: The provided patch primarily updates the script dependencies for the block editor and adjusts admin notice dismissal transients, but it does not directly address the XSS vulnerability within the block’s rendering. The actual fix for this XSS is in a separate part of the codebase, likely involving the application of `esc_html()` or `wp_kses()` to the block attributes during rendering, which is not visible in this diff. The version bump from 1.2.5 to 1.2.6 indicates the fix was released, but the diff provided does not show the core sanitization changes.

Impact: Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of a logged-in user’s session. This can lead to session hijacking, forced administrator actions (e.g., creating new admin accounts), defacement of the website, or the distribution of malware. Because the script is stored in the database, the attack persists and impacts any user who views the compromised page.

Differential between vulnerable and patched code

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

Code Diff

--- a/liquid-speech-balloon/liquid-speech-balloon.php
+++ b/liquid-speech-balloon/liquid-speech-balloon.php
@@ -8,7 +8,7 @@
 License: GPLv2
 License URI: https://www.gnu.org/licenses/gpl-2.0.html
 Text Domain: liquid-speech-balloon
-Version: 1.2.5
+Version: 1.2.6
 */
 /*  Copyright 2019 LIQUID DESIGN Ltd. (email : info@lqd.jp)

@@ -64,13 +64,11 @@

 function liquid_speech_balloon_editor_assets() {
     global $liquid_speech_balloon_name, $liquid_speech_balloon_note;
-    // enqueue
-    wp_enqueue_script( 'liquid-block-speech', plugins_url( 'lib/block.js', __FILE__ ), array( 'wp-blocks', 'wp-i18n', 'wp-element', 'wp-editor' ));
+    // enqueue（wp-editor 依存は新ウィジェットエディターで Notice が出るため wp-block-editor を使う）
+    wp_enqueue_script( 'liquid-block-speech', plugins_url( 'lib/block.js', __FILE__ ), array( 'wp-blocks', 'wp-i18n', 'wp-element', 'wp-block-editor' ));
     wp_enqueue_style( 'liquid-block-speech', plugins_url( 'css/block.css', __FILE__ ), array() );
     // inline
     wp_add_inline_style( 'liquid-block-speech', liquid_speech_balloon_style_data() );
-    // register
-    wp_register_script( 'liquid-block-speech', plugins_url( 'lib/block.js', __FILE__ ), array( 'wp-i18n' ) );
     // translations
     if ( function_exists( 'wp_set_script_translations' ) ) {
         wp_set_script_translations( 'liquid-block-speech', 'liquid-speech-balloon', plugin_dir_path( __FILE__ ) . 'languages' );
@@ -322,10 +320,10 @@
     global $liquid_speech_balloon_json;
     if( !empty($liquid_speech_balloon_json) ) {
         if ( isset( $_GET['liquid_admin_notices_dismissed'] ) ) {
-            set_transient( 'liquid_admin_notices', 'dismissed', 60*60*24*30 );
+            set_transient( 'liquid_admin_notices', 'dismissed', 60*60*24*180 );
         }
         if ( isset( $_GET['liquid_admin_offer_dismissed'] ) ) {
-            set_transient( 'liquid_admin_offer', 'dismissed', 60*60*24*30 );
+            set_transient( 'liquid_admin_offer', 'dismissed', 60*60*24*180 );
         }
         if( !empty($liquid_speech_balloon_json['news']) && get_transient( 'liquid_admin_notices' ) != 'dismissed' ){
             echo '<div class="notice notice-info" style="position: relative;"><p>'.$liquid_speech_balloon_json['news'].'</p><a href="?liquid_admin_notices_dismissed" style="position: absolute; right: 10px; top: 10px;">×</a></div>';

Frequently Asked Questions

What is CVE-2026-65527?
Vulnerability overview
CVE-2026-65527 is a stored cross-site scripting (XSS) vulnerability in the LIQUID SPEECH BALLOON WordPress plugin, affecting versions up to and including 1.2.5. It allows authenticated users with contributor-level access or higher to inject arbitrary web scripts that execute when other users view the affected page. The vulnerability has a CVSS score of 6.4 and is categorized under CWE-79.
How does the stored XSS vulnerability work?
Attack mechanism
The vulnerability arises from insufficient input sanitization and output escaping in the plugin’s block rendering logic. An attacker with contributor-level access can craft a post or page containing the Liquid Speech Balloon block and inject a malicious script into a block attribute, such as the balloon text or name field. When an administrator or other user views the published content, the script executes in their browser.
Who is affected by this vulnerability?
Affected users
Any WordPress site running LIQUID SPEECH BALLOON version 1.2.5 or earlier is affected. The attack requires an authenticated user with at least contributor-level access, so sites with multiple authors or contributors are at higher risk. Administrators and other users who view pages containing the malicious block are the ones whose sessions could be compromised.
How can I check if my site is vulnerable?
Detection steps
Check the installed version of the LIQUID SPEECH BALLOON plugin in your WordPress admin dashboard under Plugins. If the version is 1.2.5 or lower, your site is vulnerable. Additionally, review any pages or posts that use the Liquid Speech Balloon block for suspicious content, especially those authored by users with contributor-level access.
What is the practical risk of this vulnerability?
Risk assessment
The CVSS score of 6.4 indicates a medium severity. Exploitation can lead to session hijacking, forced administrative actions, website defacement, or distribution of malware. Because the script is stored in the database, the attack persists and affects any user who views the compromised page, making it a significant risk for sites with multiple users.
How does the proof of concept (PoC) demonstrate the issue?
PoC explanation
The PoC typically involves an attacker with contributor-level access creating a post with the Liquid Speech Balloon block and inserting a JavaScript payload into a block attribute, such as the balloon text. When an administrator previews or publishes the post, the script executes, demonstrating the stored XSS. This confirms that the plugin fails to sanitize output properly.
What is the root cause of the vulnerability?
Underlying issue
The root cause is the lack of proper input sanitization and output escaping in the plugin’s block rendering logic. The block attributes are not sanitized when output, allowing malicious scripts to be stored and executed. The provided patch does not directly address this, but the version bump to 1.2.6 indicates a fix was released elsewhere.
How has the vendor patched the vulnerability?
Patch details
The vendor released version 1.2.6 to address the vulnerability. Although the provided code diff mainly updates script dependencies and admin notice transients, the actual fix likely involves adding sanitization functions like esc_html() or wp_kses() to the block attributes during rendering. It is crucial to update to version 1.2.6 or later to mitigate the issue.
What steps should I take to fix or mitigate the issue?
Remediation actions
Immediately update the LIQUID SPEECH BALLOON plugin to version 1.2.6 or later. If you cannot update, consider disabling the plugin temporarily or restricting contributor-level access. Additionally, audit existing content for any injected scripts and remove them. After updating, verify that the block renders correctly and no malicious code remains.
Can this vulnerability be exploited by unauthenticated users?
Exploitation prerequisites
No, the vulnerability requires an authenticated user with at least contributor-level access. Unauthenticated users cannot directly exploit it. However, if a contributor account is compromised, the attacker could leverage this vulnerability to escalate privileges or perform other malicious actions.
Are there any other versions affected?
Version scope
The vulnerability affects all versions up to and including 1.2.5. Version 1.2.6 is the patched version. If you are using an earlier version, you should upgrade to 1.2.6 or later to ensure your site is protected.
What should I do if I suspect my site has been compromised?
Incident response
If you suspect exploitation, immediately update the plugin to the patched version, scan your site for malicious code, and review user accounts for unauthorized changes. Change all passwords, especially for administrator accounts, and consider using a security plugin to monitor for further attacks. Also, check server logs for unusual activity.

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