CVE-2026-40487 (GCVE-0-2026-40487)
Vulnerability from cvelistv5 – Published: 2026-04-18 01:19 – Updated: 2026-04-20 15:25
VLAI
EPSS
VEX
Title
Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS
Summary
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)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-20 15:25 UTC
CWE
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/gitroomhq/postiz-app/security/… | x_refsource_CONFIRM |
| https://github.com/gitroomhq/postiz-app/releases/… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| gitroomhq | postiz-app |
Affected:
< 2.21.6
|
guessed |
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