CVE-2025-66036 Overview
CVE-2025-66036 is a cross-site scripting (XSS) vulnerability affecting Retro, an online platform for vintage collection items. The flaw exists in the input handling component of the application in versions prior to 2.4.7. Attackers can inject malicious scripts through unsanitized user input, which the application renders in the browser context of other users. The maintainer addressed the issue in version 2.4.7.
Critical Impact
Successful exploitation enables attackers to execute arbitrary JavaScript in a victim's browser session, potentially leading to session token theft, credential harvesting, and unauthorized actions performed on behalf of the victim.
Affected Products
- Retro platform versions prior to 2.4.7
- GitHub repository: Anjaliavv51/Retro
- Fixed release: Retro 2.4.7
Discovery Timeline
- 2025-11-29 - CVE-2025-66036 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-66036
Vulnerability Analysis
CVE-2025-66036 is classified under [CWE-79], Improper Neutralization of Input During Web Page Generation. The Retro application fails to sanitize or encode user-supplied input before rendering it back to the browser. When a victim interacts with a crafted link or input field, the attacker-controlled payload executes in the victim's browser under the origin of the Retro application.
Because the CVSS vector indicates a changed scope with user interaction required, the vulnerability likely represents a reflected or DOM-based XSS variant. Attackers typically deliver the payload through phishing links, malicious referrers, or third-party embeds that pass unvalidated data into the vulnerable input handler.
Root Cause
The root cause is missing output encoding and input validation in the input handling component of Retro. User-controlled values reach an HTML rendering context without contextual escaping, allowing arbitrary <script> tags, event handlers, or JavaScript URIs to be interpreted as executable content.
Attack Vector
Exploitation requires an attacker to craft a URL or form input containing a JavaScript payload. The attacker delivers this link to an authenticated Retro user through phishing, social engineering, or a malicious website. When the victim opens the link, the payload executes in their session. The attacker can then exfiltrate session cookies accessible via document.cookie, capture form input, or perform authenticated requests against the Retro backend.
No verified proof-of-concept code has been published. Refer to the GitHub Security Advisory GHSA-gvv6-p6h6-2vj2 for maintainer-provided technical details.
Detection Methods for CVE-2025-66036
Indicators of Compromise
- Web server access logs containing URL parameters with <script>, onerror=, onload=, or javascript: substrings targeting Retro endpoints
- Unexpected outbound requests from user browsers to attacker-controlled domains following interaction with Retro pages
- Session anomalies such as concurrent logins from different geographies or user-agent mismatches after users click external links
Detection Strategies
- Deploy a web application firewall (WAF) with signatures for reflected XSS patterns targeting the Retro input handling endpoints
- Enable browser Content Security Policy (CSP) reporting to capture blocked inline script executions and script-src violations
- Correlate referrer headers with known phishing infrastructure and flag inbound traffic containing encoded HTML entities in query strings
Monitoring Recommendations
- Ingest Retro application access logs into a centralized logging platform and alert on parameter values containing HTML or JavaScript syntax
- Monitor authentication and session activity for anomalies immediately after users visit externally referred URLs
- Track CSP violation reports and browser telemetry for script execution attempts blocked on Retro pages
How to Mitigate CVE-2025-66036
Immediate Actions Required
- Upgrade all Retro deployments to version 2.4.7 or later without delay
- Invalidate active user sessions after upgrade to force re-authentication and revoke any tokens potentially exposed to attackers
- Review web server and application logs for exploitation attempts predating the patch
Patch Information
The Retro maintainer released version 2.4.7 to remediate CVE-2025-66036. Consult the GitHub Security Advisory GHSA-gvv6-p6h6-2vj2 for the official patch reference and commit details. Verify the deployed version against the release tag before returning the application to production.
Workarounds
- Deploy a strict Content Security Policy that disallows inline scripts and restricts script-src to trusted origins as a defense-in-depth control
- Configure a WAF rule to block requests containing common XSS payload patterns targeting Retro input parameters
- Educate users to avoid clicking Retro links received from untrusted sources until the upgrade is verified
# Example Content-Security-Policy header for Retro deployments
Content-Security-Policy: default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'; report-uri /csp-report
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
