---
cve: "CVE-2026-40487"
severity: "HIGH"
cvss: 8.9
epss: "22%"
vendor: "gitroomhq"
kev: false
exploited: false
published: "2026-04-18 02:16:11"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T03:21:58+02:00"
---

# CVE-2026-40487

> 8.9 HIGH · 🧪 PoC

## Beschreibung

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-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Erforderlich | good |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- 3ea302202dc0daa3db577eb7c68374cdc1ddbc3c (Commit)

## Referenzen

- <https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfx>
- <https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.6>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-40487) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_