CVE-2026-40925 Overview
CVE-2026-40925 is a Cross-Site Request Forgery (CSRF) vulnerability discovered in WWBN AVideo, an open source video platform. In versions 29.0 and prior, the objects/configurationUpdate.json.php endpoint (also accessible via /updateConfig) persists numerous global site settings from $_POST data but fails to implement adequate CSRF protection mechanisms. The endpoint only validates that the user is an administrator via User::isAdmin() but does not call forbidIfIsUntrustedRequest(), verify a globalToken, or validate Origin/Referer headers.
Critical Impact
A logged-in administrator visiting an attacker-controlled page can have their browser auto-submit a cross-origin POST that rewrites critical site configurations including encoder URL, SMTP credentials, site <head> HTML, logo, favicon, and contact email in a single request.
Affected Products
- WWBN AVideo versions 29.0 and prior
- AVideo installations with cross-origin iframe embedding enabled
- Self-hosted AVideo deployments using default session cookie settings
Discovery Timeline
- 2026-04-21 - CVE CVE-2026-40925 published to NVD
- 2026-04-22 - Last updated in NVD database
Technical Details for CVE-2026-40925
Vulnerability Analysis
This CSRF vulnerability exists due to a fundamental weakness in the authentication architecture of the AVideo platform. The configuration update endpoint accepts POST requests containing dozens of sensitive site settings but relies solely on session-based authentication via User::isAdmin(). The absence of anti-CSRF tokens or origin validation creates an exploitable attack surface.
The vulnerability is exacerbated by AVideo's intentional configuration of session.cookie_samesite=None to support legitimate cross-origin iframe embedding functionality. This cookie setting disables the browser's built-in SameSite cookie protection, allowing cookies to be sent with cross-origin requests and making the CSRF attack viable from any attacker-controlled website.
Root Cause
The root cause of CVE-2026-40925 is the missing CSRF protection in the objects/configurationUpdate.json.php endpoint. Specifically:
- No call to forbidIfIsUntrustedRequest() function
- No verification of a globalToken parameter
- No validation of Origin or Referer HTTP headers
- The deliberate use of session.cookie_samesite=None for cross-origin iframe support removes browser-level CSRF protection
This combination allows an attacker to craft a malicious webpage that, when visited by an authenticated administrator, automatically submits a cross-origin POST request to modify the AVideo site configuration.
Attack Vector
The attack leverages a network-based attack vector requiring user interaction. An attacker hosts a malicious webpage containing an auto-submitting HTML form or JavaScript-based request targeting the vulnerable AVideo endpoint. When an authenticated AVideo administrator visits this page, their browser automatically sends the request with their valid session cookies, allowing the attacker to modify critical site settings.
The attack can modify multiple configuration parameters in a single request, including but not limited to:
- Encoder URL (potentially redirecting video processing to attacker infrastructure)
- SMTP credentials (enabling email interception)
- Site <head> HTML (enabling XSS and malicious script injection)
- Logo and favicon (for phishing or defacement)
- Contact email (for social engineering attacks)
Detection Methods for CVE-2026-40925
Indicators of Compromise
- Unexpected changes to site configuration settings, particularly encoder URLs, SMTP credentials, or injected HTML in the site <head> section
- Configuration modifications occurring during time periods when legitimate administrators were not actively managing the platform
- Audit logs showing configuration updates from IP addresses not associated with known administrator activity
- Unusual Referer or Origin headers in web server logs for requests to /updateConfig or objects/configurationUpdate.json.php
Detection Strategies
- Monitor web server access logs for POST requests to objects/configurationUpdate.json.php or /updateConfig endpoints with suspicious or missing Referer headers
- Implement configuration change alerting to notify security teams when critical site settings are modified
- Deploy web application firewall (WAF) rules to detect and block CSRF attack patterns targeting configuration endpoints
- Review application logs for configuration changes that occur in rapid succession or from unusual geographic locations
Monitoring Recommendations
- Enable detailed logging for all administrative actions including configuration changes with full request headers
- Set up automated alerts for modifications to high-value configuration parameters such as SMTP credentials, encoder URLs, and site HTML injection points
- Implement behavioral analytics to detect anomalous administrator session activity patterns
- Monitor for new or unexpected domains appearing in encoder URL or external resource configurations
How to Mitigate CVE-2026-40925
Immediate Actions Required
- Update WWBN AVideo to a version containing commit f9492f5e6123dff0292d5bb3164fde7665dc36b4 or later
- Review current site configuration for any unauthorized changes, particularly encoder URLs, SMTP settings, and custom HTML injections
- Advise administrators to log out of AVideo sessions when not actively managing the platform
- Consider implementing network-level access controls to restrict administrative endpoint access to trusted IP ranges
Patch Information
The vulnerability has been addressed in commit f9492f5e6123dff0292d5bb3164fde7665dc36b4. Organizations running affected versions should apply this fix immediately. For more information, see the GitHub Security Advisory GHSA-vvfw-4m39-fjqf and the fix commit on GitHub.
Workarounds
- Implement a web application firewall (WAF) rule to require valid Referer/Origin headers matching the AVideo domain for all POST requests to administrative endpoints
- Consider modifying the session.cookie_samesite setting to Strict or Lax if cross-origin iframe embedding is not required for your deployment
- Restrict administrative access to the AVideo platform via VPN or IP allowlisting to reduce the attack surface
- Deploy browser isolation or separate browser profiles for administrators to prevent session sharing between administrative and general browsing activities
# Example WAF rule concept for blocking cross-origin requests to config endpoints
# Adjust syntax based on your specific WAF platform
# Block POST requests to configurationUpdate without matching origin
if (request.method == "POST" &&
request.path matches "/updateConfig|configurationUpdate.json.php" &&
request.headers["Origin"] != "https://your-avideo-domain.com") {
deny();
}
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
