Vulnerability Description
Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the `Content-Type` header. The uploaded files are then served by nginx with a Content-Type derived from their original extension (`text/html`, `image/svg+xml`), enabling Stored Cross-Site Scripting (XSS) in the context of the application's origin. This can lead to session riding, account takeover, and full compromise of other users' accounts. Version 2.21.6 contains a fix.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Gitroom | Postiz | < 2.21.6 |
Related Weaknesses (CWE)
References
- https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.6ProductRelease Notes
- https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfxExploitVendor Advisory
- https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfxExploitVendor Advisory
FAQ
What is CVE-2026-40487?
CVE-2026-40487 is a vulnerability with a CVSS score of 8.9 (HIGH). Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to th...
How severe is CVE-2026-40487?
CVE-2026-40487 has been rated HIGH with a CVSS base score of 8.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40487?
Check the references section above for vendor advisories and patch information. Affected products include: Gitroom Postiz.