CVE-2026-40487
High · 8.9CVSS
8.9
EPSS
0.3%
Published
Apr 18, 2026
CISA due date
—
The record
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.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
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Related vulnerabilities
- CVE-2026-96379 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96382 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96368 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96361 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96362 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96360 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96357 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79
- CVE-2026-96358 Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting")… CWE-79