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.
Metrics
Affected Vendors & Products
References
History
Mon, 20 Apr 2026 16:15:00 +0000
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ssvc
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Mon, 20 Apr 2026 15:15:00 +0000
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Gitroomhq
Gitroomhq postiz-app |
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| Vendors & Products |
Gitroomhq
Gitroomhq postiz-app |
Sat, 18 Apr 2026 01:45:00 +0000
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| 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. | |
| Title | Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS | |
| Weaknesses | CWE-345 CWE-434 CWE-79 |
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| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-04-18T01:19:06.588Z
Updated: 2026-04-20T15:25:40.893Z
Reserved: 2026-04-13T19:50:42.114Z
Link: CVE-2026-40487
Updated: 2026-04-20T15:25:17.386Z
Status : Awaiting Analysis
Published: 2026-04-18T02:16:11.670
Modified: 2026-04-20T19:03:07.607
Link: CVE-2026-40487
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