Summaryinfo

A vulnerability categorized as problematic has been discovered in Concrete CMS 9.4.7. Affected is the function Download of the file concrete/controllers/backend/file.php of the component File Manager. Executing a manipulation can lead to denial of service. This vulnerability is registered as CVE-2026-30662. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Concrete CMS 9.4.7. It has been declared as problematic. This vulnerability affects the function download of the file concrete/controllers/backend/file.php of the component File Manager. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

ConcreteCMS v9.4.7 contains a Denial of Service (DoS) vulnerability in the File Manager component. The 'download' method in 'concrete/controllers/backend/file.php' improperly manages memory when creating zip archives. It uses 'ZipArchive::addFromString' combined with 'file_get_contents', which loads the entire content of every selected file into PHP memory. An authenticated attacker can exploit this by requesting a bulk download of large files, triggering an Out-Of-Memory (OOM) condition that causes the PHP-FPM process to terminate (SIGSEGV) and the web server to return a 500 error.

The advisory is shared for download at wang1rrr.github.io. This vulnerability was named CVE-2026-30662 since 03/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

By approaching the search of inurl:concrete/controllers/backend/file.php it is possible to find vulnerable targets with Google Hacking.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Content Management System

Vendor

• Concrete

Name

• CMS

Version

• 9.4.7

License

• open-source

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