CVE-2026-40487

HIGH

8.9

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.

CVE Details

CVSS v3.1 Score8.9

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredLOW

User InteractionREQUIRED

Published4/18/2026

Last Modified4/18/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-79CWE-345CWE-434

References

https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.6(security-advisories@github.com)

https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfx(security-advisories@github.com)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.