CVE-2025-2220: Odyssey CMS reCAPTCHA Bypass Vulnerability

CVE-2025-2220 Overview

CVE-2025-2220 affects Odyssey CMS versions up to 10.34. The vulnerability resides in the reCAPTCHA handler within /modules/odyssey_contact_form/odyssey_contact_form.php. Attackers can manipulate the g-recaptcha-response argument to trigger a key management error caused by a hardcoded reCAPTCHA secret key [CWE-320]. Exploitation requires local access with low privileges. The exploit details have been publicly disclosed. The vendor was contacted prior to disclosure but did not respond.

Critical Impact
A hardcoded reCAPTCHA secret key in Odyssey CMS allows local, low-privileged actors to compromise the CAPTCHA validation logic, undermining bot-protection controls on the contact form module.

Affected Products

Odysseyautomation Odyssey CMS versions up to and including 10.34
Component: reCAPTCHA Handler in odyssey_contact_form.php
CPE: cpe:2.3:a:odysseyautomation:odyssey_cms:*:*:*:*:*:*:*:*

Discovery Timeline

2025-03-12 - CVE-2025-2220 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-2220

Vulnerability Analysis

The flaw is a key management error classified under [CWE-320]. Odyssey CMS ships with a reCAPTCHA secret key embedded directly in odyssey_contact_form.php. Because the secret is static and known to anyone with access to the source, the CAPTCHA validation flow can be manipulated through the g-recaptcha-response parameter. Attackers with local, low-privileged access can leverage the exposed key to influence the reCAPTCHA verification result. The confidentiality impact is limited, and there is no direct impact to integrity or availability of the underlying system.

Root Cause

The root cause is the storage of a cryptographic secret in source code rather than in a protected configuration store. Hardcoded credentials violate secure key management principles, as the secret cannot be rotated without a code change and is exposed to anyone who reads the file. This weakness enables tampering with the CAPTCHA verification workflow provided by Google reCAPTCHA.

Attack Vector

Exploitation requires local access to the affected host with low privileges. An attacker reads the hardcoded secret from /modules/odyssey_contact_form/odyssey_contact_form.php, then crafts or manipulates the g-recaptcha-response value submitted to the contact form handler. Because the secret is known, the attacker can predict or influence validation outcomes, bypassing the intended bot-protection control on the contact form. No user interaction is required.

Refer to the GitHub PoC Repository and the VulDB Vulnerability Detail for technical documentation.

Detection Methods for CVE-2025-2220

Indicators of Compromise

Presence of a hardcoded secret string within /modules/odyssey_contact_form/odyssey_contact_form.php
Unusual submission volume to the contact form endpoint with valid g-recaptcha-response values originating from non-browser clients
Contact form submissions that succeed despite reCAPTCHA challenges being disabled or misconfigured

Detection Strategies

Perform static source code review of Odyssey CMS deployments to identify embedded reCAPTCHA secret keys
Compare deployed odyssey_contact_form.php against vendor releases to detect unauthorized modifications
Correlate contact form submission logs with reCAPTCHA verification API responses to identify anomalous approvals

Monitoring Recommendations

Log all HTTP POST requests to the contact form endpoint, including the g-recaptcha-response parameter length and origin IP
Monitor file integrity on PHP module directories for unexpected changes to CAPTCHA handling code
Track outbound calls to the Google reCAPTCHA verification API and alert on validation failures followed by successful form processing

How to Mitigate CVE-2025-2220

Immediate Actions Required

Rotate the compromised reCAPTCHA secret key through the Google reCAPTCHA admin console and revoke the exposed value
Remove the hardcoded key from odyssey_contact_form.php and load the secret from a server-side environment variable or protected configuration file
Restrict filesystem permissions on the Odyssey CMS module directory to prevent local users from reading sensitive source files
Audit local user accounts on hosts running Odyssey CMS and enforce least-privilege access

Patch Information

No vendor patch or advisory is currently available. The vendor did not respond to disclosure attempts according to the VulDB record. Administrators must apply configuration and code-level workarounds until an official fix is released.

Workarounds

Replace the hardcoded secret with a reference to an environment variable or a file stored outside the web root with strict permissions
Deploy a web application firewall (WAF) rule to inspect and rate-limit contact form submissions
Disable the affected contact form module if it is not required for site operations
Enable server-side rate limiting on the contact form endpoint to reduce abuse potential

bash

# Configuration example: move reCAPTCHA secret out of source code
# 1. Set the secret as an environment variable (Apache example)
SetEnv RECAPTCHA_SECRET "your-new-rotated-secret-here"

# 2. In odyssey_contact_form.php, replace the hardcoded value:
#    $secret = getenv('RECAPTCHA_SECRET');

# 3. Restrict file permissions on the module
chown root:www-data /var/www/html/modules/odyssey_contact_form/odyssey_contact_form.php
chmod 640 /var/www/html/modules/odyssey_contact_form/odyssey_contact_form.php