CVE-2025-26759: Content Snippet Manager CSRF Vulnerability

CVE-2025-26759 Overview

CVE-2025-26759 is a Cross-Site Request Forgery (CSRF) vulnerability in the WordPress Content Snippet Manager plugin (developed by alexvtn) that enables attackers to perform Stored Cross-Site Scripting (XSS) attacks. This vulnerability affects Content Snippet Manager versions up to and including 1.1.5.

The chained CSRF-to-Stored-XSS attack vector allows malicious actors to trick authenticated administrators into executing unintended actions that inject persistent malicious scripts into the WordPress site, potentially compromising all visitors to the affected pages.

Critical Impact

Attackers can leverage this vulnerability to inject persistent malicious JavaScript code into WordPress sites, potentially leading to session hijacking, credential theft, website defacement, and malware distribution to site visitors.

Affected Products

• WordPress Content Snippet Manager plugin version 1.1.5 and earlier
• WordPress sites using vulnerable versions of content-snippet-manager

Discovery Timeline

• 2025-02-16 - CVE-2025-26759 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-26759

Vulnerability Analysis

This vulnerability combines two distinct attack vectors: Cross-Site Request Forgery (CWE-352) and Stored Cross-Site Scripting. The Content Snippet Manager plugin fails to properly implement CSRF protection tokens on forms that handle content snippet creation or modification. This missing validation allows attackers to craft malicious requests that, when executed by an authenticated administrator, inject arbitrary JavaScript code into stored content snippets.

The stored XSS payload persists in the WordPress database and executes whenever the affected snippet is rendered on the front-end or back-end of the WordPress site. This persistence makes the attack particularly dangerous as it can affect multiple users over an extended period without requiring further attacker interaction.

Root Cause

The root cause of this vulnerability lies in the plugin's failure to implement proper CSRF token validation on state-changing operations. The Content Snippet Manager plugin does not verify nonce tokens when processing form submissions that create or modify content snippets. Additionally, the plugin lacks adequate output encoding and input sanitization for user-supplied content, allowing malicious JavaScript payloads to be stored and subsequently rendered without proper escaping.

Attack Vector

The attack requires an attacker to craft a malicious HTML page or link containing a forged request targeting the vulnerable plugin endpoint. When an authenticated WordPress administrator with sufficient privileges visits the attacker-controlled page or clicks the malicious link, their browser automatically submits the forged request to the WordPress site. This request carries the administrator's authenticated session, allowing the malicious content snippet containing XSS payload to be created or modified.

Once the malicious snippet is stored, any user who views a page containing the snippet will have the malicious JavaScript executed in their browser context. This can lead to session token theft, keylogging, phishing attacks, drive-by downloads, and complete site compromise if administrator sessions are hijacked.

Detection Methods for CVE-2025-26759

Indicators of Compromise

• Unexpected or unfamiliar content snippets in the Content Snippet Manager plugin settings
• JavaScript code embedded within content snippets, particularly containing <script> tags or event handlers
• Administrator session cookies being sent to external domains
• Unusual administrative actions in WordPress audit logs without corresponding legitimate user activity

Detection Strategies

• Review Content Snippet Manager entries for suspicious JavaScript content or encoded payloads
• Monitor HTTP request logs for unusual POST requests to plugin endpoints from external referrers
• Implement Content Security Policy (CSP) headers and monitor for policy violations
• Deploy web application firewall (WAF) rules to detect CSRF and XSS attack patterns

Monitoring Recommendations

• Enable WordPress audit logging to track all changes to content snippets
• Configure browser-based XSS detection mechanisms and CSP reporting
• Monitor for outbound connections from the WordPress site to unknown external domains
• Regularly review plugin-stored content for unauthorized modifications

How to Mitigate CVE-2025-26759

Immediate Actions Required

• Disable or remove the Content Snippet Manager plugin until a patched version is available
• Review all existing content snippets for malicious JavaScript and remove any suspicious entries
• Rotate administrator credentials and invalidate existing sessions if compromise is suspected
• Implement a Web Application Firewall with CSRF and XSS protection rules

Patch Information

At the time of this advisory, users should check the Patchstack Vulnerability Advisory for the latest remediation guidance and patch availability. If a patched version is not available, consider migrating to an alternative content snippet management solution with proper security controls.

Workarounds

• Disable the Content Snippet Manager plugin entirely until a security patch is released
• Restrict administrator access to trusted IP addresses using .htaccess or WordPress security plugins
• Implement HTTP referrer validation at the server level to reject requests from external origins
• Deploy Content Security Policy headers to mitigate the impact of stored XSS payloads
• Train administrators to avoid clicking untrusted links while logged into WordPress

# Example: Add CSP headers in .htaccess to mitigate XSS impact
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"
    Header set X-Content-Type-Options "nosniff"
    Header set X-XSS-Protection "1; mode=block"
</IfModule>