CVE-2026-35569: Stored XSS in SEO Fields Leads to Authenticated API Data Exposure in ApostropheCMS

April 16, 2026 (updated April 30, 2026)

A stored cross-site scripting (XSS) vulnerability exists in SEO-related fields (SEO Title and Meta Description) in ApostropheCMS.

Improper neutralization of user-controlled input in SEO-related fields allows injection of arbitrary JavaScript into HTML contexts, resulting in stored cross-site scripting (XSS). This can be leveraged to perform authenticated API requests and exfiltrate sensitive data, resulting in a compromise of application confidentiality.

References

github.com/Chittu13/cve-research/tree/main/CVE-2026-35569
github.com/advisories/GHSA-855c-r2vq-c292
github.com/apostrophecms/apostrophe/commit/0e57dd07a56ae1ba1e3af646ba026db4d0ab5bb3
github.com/apostrophecms/apostrophe/security/advisories/GHSA-855c-r2vq-c292
nvd.nist.gov/vuln/detail/CVE-2026-35569

Code Behaviors & Features

Detect and mitigate CVE-2026-35569 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →