# CVE-2026-40487

> Vulnerability · severity: **HIGH** (CVSS 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.

## Key facts

- **CVE ID:** CVE-2026-40487
- **Published:** 2026-04-18
- **CVSS severity:** HIGH
- **CVSS base score:** 8.9
- **CWE codes:** CWE-79, CWE-345, CWE-434

## Affected products

- `gitroom:postiz`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40487

## Citation

> AI Analytics. CVE-2026-40487. Retrieved 2026-07-10 from https://api.ai-analytics.org/cve/CVE-2026-40487. Derived from NIST NVD. Licensed CC0.

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