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Findings

CVE-2026-40487

Postiz is an AI social media scheduling tool.

Published Apr 18, 2026 · updated Jun 17, 2026 · gitroom postiz

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 header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), 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.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 18, 2026 · NIST NVD

    Detected

    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 header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), enabling Stored Cross-Site Scripting (XSS) in the context

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), enabling Stored Cross-Site Scripting (XSS) in the context

Affected

  • cpe gitroom/postizversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2026-40487

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-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, SVG, or other executable file types to the server by spoofing the header. The uploaded files are then serv

    nvd.nist.gov

References