CVE-2025-65840: PublicCMS CSRF Vulnerability

CVE-2025-65840 Overview

CVE-2025-65840 is a Cross-Site Request Forgery (CSRF) vulnerability affecting PublicCMS V5.202506.b. The vulnerability exists in the CkEditorAdminController component, allowing attackers to trick authenticated administrators into performing unintended actions on the CMS application. By crafting malicious requests and enticing victims to visit attacker-controlled pages, threat actors can execute administrative operations without proper authorization validation.

Critical Impact

This HIGH severity CSRF vulnerability (CVSS 8.8) enables attackers to perform unauthorized actions with full administrative privileges, potentially leading to complete compromise of the PublicCMS installation including data modification, user account manipulation, and system configuration changes.

Affected Products

• PublicCMS V5.202506.b
• PublicCMS CkEditorAdminController component

Discovery Timeline

• 2025-12-01 - CVE-2025-65840 published to NVD
• 2025-12-04 - Last updated in NVD database

Technical Details for CVE-2025-65840

Vulnerability Analysis

The CSRF vulnerability in PublicCMS V5.202506.b stems from inadequate request validation in the CkEditorAdminController component. This controller fails to implement proper anti-CSRF token mechanisms, allowing cross-origin requests to be processed as legitimate administrative actions.

The vulnerability is classified under CWE-352 (Cross-Site Request Forgery), which occurs when a web application does not sufficiently verify that a request was intentionally provided by the user who submitted it. The CVSS 3.1 vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H indicates:

• Attack Vector (AV:N): Network-based exploitation
• Attack Complexity (AC:L): Low complexity required
• Privileges Required (PR:N): No privileges needed by attacker
• User Interaction (UI:R): Requires victim interaction
• Impact: High confidentiality, integrity, and availability impact

Root Cause

The root cause of CVE-2025-65840 is the absence of CSRF protection mechanisms in the CkEditorAdminController. The controller processes state-changing requests without validating the origin of the request or requiring a synchronizer token. This allows attackers to forge requests that appear legitimate to the server when submitted by an authenticated administrator's browser.

Attack Vector

The attack vector involves crafting a malicious HTML page or email containing hidden forms or JavaScript that automatically submits requests to the vulnerable PublicCMS endpoint. When an authenticated administrator visits the attacker's page, their browser automatically includes session cookies with the forged request, causing the server to process it as a legitimate administrative action.

The vulnerability can be exploited through various delivery mechanisms including:

• Malicious links sent via email or messaging platforms
• Compromised or malicious websites visited by the victim
• Injected content through other web vulnerabilities

Technical details and proof-of-concept information can be found in the referenced security advisories at the GitHub issue tracker and third-party advisory repositories.

Detection Methods for CVE-2025-65840

Indicators of Compromise

• Unexpected administrative actions in PublicCMS audit logs
• HTTP requests to CkEditorAdminController endpoints from external referrers
• Unusual patterns of administrative operations without corresponding admin login activity
• POST requests to administrative endpoints with missing or invalid CSRF tokens

Detection Strategies

Organizations can detect potential exploitation attempts by monitoring web application logs for suspicious patterns:

1. Referrer Analysis: Flag requests to administrative endpoints where the HTTP Referer header points to external domains
2. Session Correlation: Monitor for administrative actions that occur shortly after a user visits external websites
3. Behavioral Analysis: Identify anomalous administrative operations that deviate from normal patterns
4. Web Application Firewall (WAF) Rules: Implement rules to detect and block requests to sensitive endpoints lacking proper origin validation

The current EPSS score is 0.017% (percentile: 3.154), indicating a relatively low probability of active exploitation in the wild at this time.

Monitoring Recommendations

• Enable comprehensive logging for all administrative controller actions in PublicCMS
• Configure alerts for administrative operations originating from suspicious referrers
• Implement real-time monitoring of CkEditorAdminController endpoint access patterns
• Deploy network-based detection for unusual POST request patterns to administrative endpoints

How to Mitigate CVE-2025-65840

Immediate Actions Required

• Restrict access to PublicCMS administrative interfaces to trusted networks only
• Implement Web Application Firewall (WAF) rules to validate request origins
• Educate administrators about CSRF attack risks and safe browsing practices while authenticated
• Consider implementing additional authentication steps for sensitive administrative operations

Patch Information

As of the last update on 2025-12-04, no official patch information has been published by the vendor. Organizations should monitor the official PublicCMS GitHub repository at https://github.com/sanluan/PublicCMS for security updates and patch releases. The vulnerability is tracked in GitHub issue #102.

Workarounds

In the absence of an official patch, organizations can implement the following defensive measures:

Configure reverse proxy or WAF rules to validate request origins:

# Nginx configuration to validate referrer for admin endpoints
location /admin/ {
    if ($http_referer !~* "^https?://your-trusted-domain\.com") {
        return 403;
    }
    proxy_pass http://publiccms_backend;
}

Additional workaround measures include:

• Restricting administrative access to VPN-only connections
• Implementing IP-based access controls for administrative endpoints
• Using browser extensions that isolate sessions between tabs
• Logging out of PublicCMS before browsing other websites