# CVE-2026-40487: Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any…

Source: https://junglewise.ai/threats/cve-2026-40487-postiz-is-an-ai-social-media-scheduling-tool-prior-to-version-2  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-18  
License: CC BY 4.0 with a link back

CVE-2026-40487 · Severity: high · CVSS 8.9 · Published 2026-04-18

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.

Technologies: [Gitroom Postiz](https://junglewise.ai/threats/technologies/postiz). Vendors: [Gitroom](https://junglewise.ai/threats/vendors/gitroom).

## Quick answers

**Is CVE-2026-40487 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-40487 being exploited in the wild.

**How severe is CVE-2026-40487?** High severity, with a CVSS score of 8.9, published 18 April 2026.

**Which products and versions are affected?** Gitroom Postiz. The advisory does not name versions.

**Is there a fix for CVE-2026-40487?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-40487?** Check whether you run Gitroom Postiz. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Gitroom Postiz

## Related threats

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- [Postiz SSRF via DNS Rebinding TOCTOU in URL Validation](https://junglewise.ai/threats/cve-2026-42346-postiz-ssrf-via-dns-rebinding-toctou-in-url-validation)