{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "5.18.2"
              },
              {
                "fixed": "5.21.1"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "fdd41fcc9acb3cddb80b3f4098c820709193f457"
            },
            {
              "fixed": "a70ea49624f291319cfe66dd9b53200e25cd3bcd"
            }
          ],
          "repo": "https://github.com/redaxo/core",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-98pp-vccm-qm25"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-434"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53599.json"
  },
  "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.",
  "id": "CVE-2026-53599",
  "modified": "2026-08-04T11:31:15.181032374Z",
  "published": "2026-07-31T19:43:15.663Z",
  "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"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Redaxo has a Mediapool isAllowedExtension bypass via multi-segment filename that leads to authenticated RCE on Apache mod_php multi-extension handlers"
}