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.
{
"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"
}{
"extracted_events": [
{
"range": [
{
"introduced": "5.18.2"
},
{
"fixed": "5.21.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "462e36896bb65d292ba22d711044c23c9cfb0340"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "5.21.1",
"range": [
{
"fixed": "a70ea49624f291319cfe66dd9b53200e25cd3bcd"
}
],
"source": "REFERENCES_TAG"
}
]
}