Vulnerability Description
ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in SEO-related fields (SEO Title and Meta Description), where user-controlled input is rendered without proper output encoding into HTML contexts including <title> tags, <meta> attributes, and JSON-LD structured data. An attacker can inject a payload such as "></title><script>alert(1)</script> to break out of the intended HTML context and execute arbitrary JavaScript in the browser of any authenticated user who views the affected page. This can be leveraged to perform authenticated API requests, access sensitive data such as usernames, email addresses, and roles via internal APIs, and exfiltrate it to an attacker-controlled server. This issue has been fixed in version 4.29.0.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apostrophecms | Apostrophecms | < 4.29.0 |
Related Weaknesses (CWE)
References
- https://github.com/Chittu13/cve-research/tree/main/CVE-2026-35569
- https://github.com/apostrophecms/apostrophe/commit/0e57dd07a56ae1ba1e3af646ba026Patch
- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-855c-r2vq-cExploitPatchVendor Advisory
FAQ
What is CVE-2026-35569?
CVE-2026-35569 is a vulnerability with a CVSS score of 8.7 (HIGH). ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in SEO-related fields (SEO Title and Meta Description),...
How severe is CVE-2026-35569?
CVE-2026-35569 has been rated HIGH with a CVSS base score of 8.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-35569?
Check the references section above for vendor advisories and patch information. Affected products include: Apostrophecms Apostrophecms.