CVEvulnerability

CVE-2026-40487

9.0 CRITICAL Published 2026-04-18 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-04-18
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.9 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
CVSS 3.1 ([email protected])
9.0 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Weaknesses
CWE-345, CWE-434, CWE-79

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.

Affected configurations

• gitroom postiz (< 2.21.6)

Related

Weakness · CWE (3)

  • CWE-345 Insufficient Verification of Data Authenticity weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References