CVE Catalog

CVE-2026-104890

HighCVSS 7.2
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.42%

34th percentile - higher than 34% of all known CVEs

Summary

Kunstmaan CMS prior to 7.3.2 performs the blacklisted_extensions check case-sensitively in FileHandler::getFilePath and then lowercases the stored extension. 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.

Risk Assessment

An authenticated backend user can upload and execute malicious code on the server, leading to remote code execution and full system compromise. The risk is high in environments where the web server executes uploaded files.

Recommendation

Update Kunstmaan CMS to version 7.3.2. Until then, extend the blacklist to cover all executable extensions and enforce case-insensitive checking.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS