CVE-2026-40487

CRITICAL EPSS 13.0%
Published Apr 18, 20262mo ago · Modified Jun 17, 20262w ago
9.0 CVSS 3.1
Critical
Find Similar
Published Apr 18, 2026 2mo ago
Last Modified Jun 17, 2026 2w 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.

CVSS Details

Base Score
9.0
Exploitability
2.3
Impact
6.0
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction Required
Scope Changed
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
13.0% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 3

CWE-345
CWE-434 Unrestricted Upload of File with Dangerous Type Resource Mgmt
CWE-79 Cross-site Scripting Injection

Affected Products 1

VendorProductVersionRange
gitroompostiz* <2.21.6

References 2

  • github.com https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.6
    ProductRelease Notes
  • github.com https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfx
    ExploitVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.