{"id":"CVE-2026-104890","aliases":["EUVD-2026-92446","GHSA-p279-5wcv-45vq"],"status":"published","title":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","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.","severity":{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00416,"percentile":0.36371,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-434"],"published":"2026-10-05T15:46:21Z","modified":"2026-11-11T02:48:40Z","fixes":[{"ecosystem":"Packagist","package":"kunstmaan/media-bundle","fixed_in":["7.3.2"],"sources":["ghsa","osv"]},{"ecosystem":"Packagist","package":"kunstmaan/bundles-cms","fixed_in":["7.3.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"kunstmaan/media-bundle","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.3.2"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"kunstmaan/bundles-cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.3.2"}]}]},{"source":"osv","ecosystem":"Packagist","package":"kunstmaan/media-bundle","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.3.2"}]}],"versions":["3.0.0","3.0.1","3.0.2","3.0.3","3.1.0","3.1.1","3.1.2","3.1.3","3.1.4","3.2.0","3.2.1","3.2.1.1","3.2.2","3.2.3","3.2.4","3.2.4.1","3.2.5","3.2.6","3.3.0","3.3.1","3.3.2","3.3.3","3.3.4","3.4.0","3.4.1","3.4.2","3.5.0","3.5.1","3.5.2","3.6.0","3.6.1","3.6.2","3.6.3","4.0.0","4.0.0-RC1","4.0.1","4.0.2","4.0.3","4.1.0","4.1.1","4.1.2","4.1.3","4.1.4","4.2.0","4.2.1","4.2.2","4.2.3","5.0.0","5.0.0-RC1","5.0.0-RC2","5.0.1","5.0.10","5.0.11","5.0.12","5.0.13","5.0.14","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.0.7","5.0.9","5.1.0","5.1.1","5.1.2","5.10.0","5.10.1","5.10.2","5.10.3","5.10.4","5.10.5","5.10.6","5.10.7","5.2.0","5.2.1","5.2.2","5.2.3","5.2.4","5.2.5","5.3.0","5.3.1","5.3.10","5.3.11","5.3.12","5.3.13","5.3.14","5.3.2","5.3.3","5.3.4","5.3.5","5.3.7","5.3.8","5.3.9","5.4.0","5.4.1","5.4.2","5.4.3","5.4.4","5.4.5","5.4.6","5.4.7","5.5.0","5.5.1","5.5.2","5.5.3","5.5.4","5.5.5","5.5.6","5.6.0","5.6.1","5.6.2","5.6.3","5.6.4","5.6.5","5.6.6","5.7.0","5.7.1","5.7.2","5.7.3","5.8.0","5.8.1","5.9.0","5.9.1","5.9.2","5.9.3","6.0.0","6.0.1","6.0.2","6.0.3","6.0.4","6.0.5","6.0.6","6.1.0","6.1.1","6.1.2","6.1.3","6.1.4","6.1.5","6.1.6","6.1.7","6.1.8","6.1.9","6.2.0","6.2.1","6.2.2","6.2.3","6.2.4","6.2.5","6.3.0","6.3.1","6.4.0","6.4.0-alpha1","6.4.0-alpha2","6.4.1","6.4.2","6.4.3","6.4.4","7.0.0","7.0.0-alpha1","7.0.1","7.0.2","7.0.3","7.0.4","7.0.5","7.1.0","7.1.0-alpha1","7.1.0-alpha2","7.1.1","7.1.2","7.1.3","7.1.4","7.2.0","7.2.1","7.3.0","7.3.1","v1.3","v1.3.1","v1.3.2","v1.3.3","v2.1","v2.1.1","v2.1.2","v2.1.3","v2.2","v2.2.1","v2.2.10","v2.2.2","v2.2.3","v2.2.8","v2.2.9","v2.3","v2.3.1","v2.3.10","v2.3.11","v2.3.12","v2.3.13","v2.3.14","v2.3.15","v2.3.16","v2.3.17","v2.3.18","v2.3.19","v2.3.2","v2.3.20","v2.3.21","v2.3.22","v2.3.23","v2.3.3","v2.3.4","v2.3.5","v2.3.6","v2.3.7","v2.3.8","v2.3.9"]},{"source":"osv","ecosystem":"Packagist","package":"kunstmaan/bundles-cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.3.2"}]}],"versions":["3.0.0","3.0.1","3.0.2","3.0.3","3.1.0","3.1.1","3.1.2","3.1.3","3.1.4","3.2.0","3.2.1","3.2.1.1","3.2.2","3.2.3","3.2.4","3.2.4.1","3.2.5","3.2.6","3.3.0","3.3.1","3.3.2","3.3.3","3.3.4","3.4.0","3.4.1","3.4.2","3.5.0","3.5.1","3.5.2","3.6.0","3.6.1","3.6.2","3.6.3","4.0.0","4.0.0-RC1","4.0.1","4.0.2","4.0.3","4.1.0","4.1.1","4.1.2","4.1.3","4.1.4","4.2.0","4.2.1","4.2.2","4.2.3","5.0.0","5.0.0-RC1","5.0.0-RC2","5.0.1","5.0.10","5.0.11","5.0.12","5.0.13","5.0.14","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.0.7","5.0.8","5.0.9","5.1.0","5.1.1","5.1.2","5.10.0","5.10.1","5.10.2","5.10.3","5.10.4","5.10.5","5.10.6","5.10.7","5.2.0","5.2.1","5.2.2","5.2.3","5.2.4","5.2.5","5.3.0","5.3.1","5.3.10","5.3.11","5.3.12","5.3.13","5.3.14","5.3.2","5.3.3","5.3.4","5.3.5","5.3.6","5.3.7","5.3.8","5.3.9","5.4.0","5.4.1","5.4.2","5.4.3","5.4.4","5.4.5","5.4.6","5.4.7","5.5.0","5.5.1","5.5.2","5.5.3","5.5.4","5.5.5","5.5.6","5.6.0","5.6.1","5.6.2","5.6.3","5.6.4","5.6.5","5.6.6","5.7.0","5.7.1","5.7.2","5.7.3","5.8.0","5.8.1","5.9.0","5.9.1","5.9.2","5.9.3","6.0.0","6.0.1","6.0.2","6.0.3","6.0.4","6.0.5","6.0.6","6.1.0","6.1.1","6.1.2","6.1.3","6.1.4","6.1.5","6.1.6","6.1.7","6.1.8","6.1.9","6.2.0","6.2.1","6.2.2","6.2.3","6.2.4","6.2.5","6.3.0","6.3.1","6.4.0","6.4.0-alpha1","6.4.0-alpha2","6.4.1","6.4.2","6.4.3","6.4.4","7.0.0","7.0.0-alpha1","7.0.1","7.0.2","7.0.3","7.0.4","7.0.5","7.1.0","7.1.0-alpha1","7.1.0-alpha2","7.1.1","7.1.2","7.1.3","7.1.4","7.2.0","7.2.1","7.3.0","7.3.1"]}],"products":[{"vendor":"kunstmaan","product":"bundles-cms"},{"vendor":"kunstmaan","product":"kunstmaanbundlescms"},{"vendor":"kunstmaan","product":"media-bundle"}],"references":[{"url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/security/advisories/GHSA-p279-5wcv-45vq","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/commit/1bbdfdeac8e7e91506b1a9271360b9b68d7690d3","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS/releases/tag/7.3.2","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104890","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-p279-5wcv-45vq"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104890.json","tags":["advisory"]},{"url":"https://github.com/Kunstmaan/KunstmaanBundlesCMS","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-104890","title":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","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.","status":"published","published":"2026-10-05T15:46:21.959Z","modified":"2026-10-07T20:50:50.492Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:20:09.098623Z"}],"euvd":[{"id":"EUVD-2026-92446","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.","status":"published","published":"2026-10-05T15:46:21Z","modified":"2026-10-07T20:50:50Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T17:27:33.555595Z"}],"ghsa":[{"id":"GHSA-p279-5wcv-45vq","title":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","description":"### Summary\n\nThe MediaBundle blocks dangerous upload extensions with a blacklist that was matched\ncase-sensitively, while the stored filename was lowercased afterwards. A file uploaded\nas `webshell.pHp` therefore bypassed the blacklist and was written to the web-accessible\nupload directory as `webshell.php`, where the web server executed it. Any authenticated\nbackend user with access to the media section could obtain remote code execution.\n\n### Details\n\n`FileHandler::getFilePath()` rewrote blacklisted extensions to `.txt` using a\ncase-sensitive regex, and only then lowercased the extension when building the stored\nname — so the check ran against the attacker-controlled casing and the normalisation\nhappened after it.\n\nTwo further weaknesses contributed:\n\n* The default blacklist contained only `php` and `htaccess`, leaving other\n  server-executable extensions (`phtml`, `php5`, `phar`, `shtml`, `cgi`, …) unblocked\n  regardless of casing.\n* Configured blacklist values were interpolated into the regex unescaped.\n\n### Impact\n\nAn authenticated user with access to the admin media section can upload a file that the\nweb server executes as PHP. The uploaded file is reachable over HTTP without\nauthentication, giving arbitrary code execution as the web server user.\n\n### Patches\n\nFixed in kunstmaan/media-bundle 7.3.2. The extension is now normalised before it is\nchecked and compared with `in_array()`; the default blacklist is expanded to the full\nset of server-executable extensions; and a new opt-in `allowed_extensions` option allows\nprojects to enforce a strict allow-list.\n\nNote that the patch does not rename files already stored on disk. Sites should audit\ntheir media upload directory for existing files with an executable extension.\n\n### Workarounds\n\nIf you cannot upgrade, configure the web server to refuse to execute scripts in the\nmedia upload directory (for example a `location` block in nginx or `php_flag engine off`\nin Apache).","status":"published","published":"2026-10-07T18:05:38Z","modified":"2026-10-07T18:05:42Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:41:28.013673Z"}],"nvd":[{"id":"CVE-2026-104890","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.","status":"published","published":"2026-10-05T16:17:06.27Z","modified":"2026-10-07T21:17:09.367Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:12:53.75133Z"}],"osv":[{"id":"CVE-2026-104890","title":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","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.","status":"published","published":"2026-10-05T15:46:21.959Z","modified":"2026-11-11T10:47:23.037198834Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-434"],"updated_at":"2026-11-11T03:22:04.464623Z"},{"id":"GHSA-p279-5wcv-45vq","title":"Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution","description":"### Summary\n\nThe MediaBundle blocks dangerous upload extensions with a blacklist that was matched\ncase-sensitively, while the stored filename was lowercased afterwards. A file uploaded\nas `webshell.pHp` therefore bypassed the blacklist and was written to the web-accessible\nupload directory as `webshell.php`, where the web server executed it. Any authenticated\nbackend user with access to the media section could obtain remote code execution.\n\n### Details\n\n`FileHandler::getFilePath()` rewrote blacklisted extensions to `.txt` using a\ncase-sensitive regex, and only then lowercased the extension when building the stored\nname — so the check ran against the attacker-controlled casing and the normalisation\nhappened after it.\n\nTwo further weaknesses contributed:\n\n* The default blacklist contained only `php` and `htaccess`, leaving other\n  server-executable extensions (`phtml`, `php5`, `phar`, `shtml`, `cgi`, …) unblocked\n  regardless of casing.\n* Configured blacklist values were interpolated into the regex unescaped.\n\n### Impact\n\nAn authenticated user with access to the admin media section can upload a file that the\nweb server executes as PHP. The uploaded file is reachable over HTTP without\nauthentication, giving arbitrary code execution as the web server user.\n\n### Patches\n\nFixed in kunstmaan/media-bundle 7.3.2. The extension is now normalised before it is\nchecked and compared with `in_array()`; the default blacklist is expanded to the full\nset of server-executable extensions; and a new opt-in `allowed_extensions` option allows\nprojects to enforce a strict allow-list.\n\nNote that the patch does not rename files already stored on disk. Sites should audit\ntheir media upload directory for existing files with an executable extension.\n\n### Workarounds\n\nIf you cannot upgrade, configure the web server to refuse to execute scripts in the\nmedia upload directory (for example a `location` block in nginx or `php_flag engine off`\nin Apache).","status":"published","published":"2026-10-07T18:05:38Z","modified":"2026-10-07T18:15:11.799807414Z","cvss":[{"version":"3.1","score":7.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T15:46:52.534897Z"}]}}