{"id":"CVE-2026-53599","aliases":["GHSA-98pp-vccm-qm25"],"url":"https://o3.security/vulnerability/CVE-2026-53599","summary":"Redaxo has a Mediapool isAllowedExtension bypass via multi-segment filename that leads to authenticated RCE on Apache mod_php multi-extension handlers","details":"REDAXO is a PHP-based content management system. From 5.18.2 until 5.21.1, rex_mediapool::isAllowedExtension in redaxo/src/addons/mediapool/lib/mediapool.php lets an authenticated backend user with media[upload] permission upload a JPEG/PHP polyglot named shell.php.any.jpg, which web servers with multi-extension PHP handlers can execute as the web-server user. This issue is fixed in version 5.21.1.","published":"2026-07-31T19:43:15.663Z","modified":"2026-09-11T03:30:18.116598141Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00395,"percentile":0.33079,"asOf":"2026-09-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"redaxo/source","fixedVersion":"5.21.1"}],"fix":{"url":"https://github.com/redaxo/core/commit/462e36896bb65d292ba22d711044c23c9cfb0340","label":"redaxo/core@462e368"},"references":[{"type":"WEB","url":"https://github.com/redaxo/core/releases/tag/5.21.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53599.json"},{"type":"ADVISORY","url":"https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53599"},{"type":"FIX","url":"https://github.com/redaxo/core/commit/462e36896bb65d292ba22d711044c23c9cfb0340"},{"type":"FIX","url":"https://github.com/redaxo/core/pull/6538"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:30:18.116598141Z"}}