CVE-2026-104890 · GHSA-p279-5wcv-45vq
Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution
- Risk score
- 60/100
- CVSS
- 7.2 v3.1
- Exploit chance (30 days)
- 0.4%
- Published
- 5 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Kunstmaan CMS is an open source content management system based on the Symfony framework. Prior to 7.3.2, src/Kunstmaan/MediaBundle/Helper/File/FileHandler.php performs the blacklisted_extensions check case-sensitively in FileHandler::getFilePath and lowercases the stored extension afterward. An authenticated backend …
- Affected
- kunstmaan/media-bundle (composer) < 7.3.2; kunstmaan/bundles-cms (composer) < 7.3.2
- Fix
- Upgrade kunstmaan/media-bundle to 7.3.2; kunstmaan/bundles-cms to 7.3.2 or later.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 7.2 high
- On your watchlist: php, Composer
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| kunstmaan/media-bundle | composer | < 7.3.2 | 7.3.2 |
| kunstmaan/bundles-cms | composer | < 7.3.2 | 7.3.2 |
References
- https://github.com/advisories/GHSA-p279-5wcv-45vq
- https://github.com/Kunstmaan/KunstmaanBundlesCMS/security/advisories/GHSA-p279-5wcv-45vq
- https://nvd.nist.gov/vuln/detail/CVE-2026-104890
- https://github.com/Kunstmaan/KunstmaanBundlesCMS/commit/1bbdfdeac8e7e91506b1a9271360b9b68d7690d3
- https://github.com/Kunstmaan/KunstmaanBundlesCMS/releases/tag/7.3.2
- https://github.com/advisories/GHSA-p279-5wcv-45vq
Original description
Kunstmaan CMS is an open source content management system based on the Symfony framework. Prior to 7.3.2, src/Kunstmaan/MediaBundle/Helper/File/FileHandler.php performs the blacklisted_extensions check case-sensitively in FileHandler::getFilePath and lowercases the stored extension afterward. An authenticated backend user with media access can upload a mixed-case executable extension such as PHP that bypasses the check and is stored in the web-accessible media directory with an executable lowercase extension. The default blacklist also omits several server-executable extension types, allowing the same code-execution impact where the web server executes uploaded files. This issue is fixed in version 7.3.2.
Last activity 5 Oct 2026. Patch Forecast updates every hour.