CVE-2026-40487: Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any…
CVE-2026-40487 · Severity: high · CVSS 8.9 · Published 2026-04-18
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.
No. Junglewise Threat Intelligence has no report of CVE-2026-40487 being exploited in the wild.
How severe is CVE-2026-40487?
High severity, with a CVSS score of 8.9, published 18 April 2026.
Which products and versions are affected?
Gitroom Postiz. The advisory does not name versions.
Is there a fix for CVE-2026-40487?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-40487?
Check whether you run Gitroom Postiz. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.