CVE-2026-40487: 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…

PriorityP345critical9CVSS 3.1

AVNACLPRLUIRSCCHIHAH

EPSS

0.22%

13.0th percentile

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
gitroom	postiz	< 2.21.6	2.21.6
gitroomhq	postiz-app	< 2.21.6	2.21.6

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