{"id":"CVE-2026-104890","summary":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","details":"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.","aliases":["GHSA-p279-5wcv-45vq"],"modified":"2026-10-07T02:47:26.525980161Z","published":"2026-10-05T15:46:21.959Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-434"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104890.json"},"references":[{"type":"WEB","url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/releases/tag/7.3.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104890.json"},{"type":"ADVISORY","url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/security/advisories/GHSA-p279-5wcv-45vq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104890"},{"type":"FIX","url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/commit/1bbdfdeac8e7e91506b1a9271360b9b68d7690d3"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/kunstmaan/kunstmaanbundlescms","events":[{"introduced":"0"},{"fixed":"1bbdfdeac8e7e91506b1a9271360b9b68d7690d3"},{"fixed":"0f8fb55a7408a92afd34504682a9adc253d34401"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"7.3.1"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["7.3.1","7.3.0","7.1.0-alpha1","5.3.0","5.2.0","5.1.0","5.0.2","5.0.1","5.0.0","5.0.0-RC2","5.0.0-RC1","4.0.0","4.0.0-RC1","3.5.0","3.2.0","3.4.2","3.4.1","3.1.2","3.2.4.1","3.4.0","3.3.2","3.3.1","3.3.0","3.2.3","3.2.4","3.2.2","3.2.1.1","3.2.1","3.1.1","3.1.0","3.0.2","3.0.1","3.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-104890.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"}]}