CVE-2026-40487: high-severity vulnerability in gitroomhq postiz-app
Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.9epss 0.2%
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:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
Affected products
gitroomhq · postiz-appRelated CVEs — gitroomhq postiz-app
In the same product, most dangerous first.
CVE-2026-19264CRITICALUnauthenticated arbitrary file read via /uploads path traversal (URL-encoded separators) leading to instance takeoverEPSS 1.0%CVE-2026-42298CRITICALPostiz: Arbitrary Code Execution and Token Exfiltration in pr-docker-build.yml via untrusted Dockerfile.devEPSS 0.5%CVE-2026-34577HIGHPostiz: Unauthenticated Full-Read SSRF via /public/stream Endpoint with Trivially Bypassable Extension CheckEPSS 0.5%CVE-2026-40168HIGHPostiz has Server-Side Request Forgery via Redirect Bypass in /api/public/streamEPSS 0.4%CVE-2025-53641HIGHPostiz allows header mutation in middleware facilitates resulting in SSRFEPSS 0.3%CVE-2026-34576HIGHPostiz: SSRF in upload-from-url endpoint allows fetching internal resources and cloud metadataEPSS 0.3%