Report: CVE-2026-40487 - Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS - Guide
CVE ID :CVE-2026-40487 Published : April 18, 2026, 2:16 a.m. | 1 hour, 17 minutes ago 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. Severity: 8.9 | HIGH Visit the link for more details, such as CVSS details, affected products, timeline, and more...