High 7.2Published Oct 5, 2026

CVE-2026-104890Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution

Updated under an hour ago (2026-10-19 07:30 UTC)

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It affects KunstmaanBundlesCMS and 2 other products. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.42%, higher than 34% of scored CVEs.

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Every CVE for KunstmaanBundlesCMS

Exploited in the last 30 days

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.

CVSS: 7.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-434
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.42% (percentile 34)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 7, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Kunstmaan KunstmaanBundlesCMS kunstmaan:kunstmaanbundlescms (from the name)	before 7.3.1	CNA record
kunstmaan bundles-cms kunstmaan:bundles_cms (from the name)	before 7.3.1	CNA record
kunstmaan media-bundle kunstmaan:media_bundle (from the name)	before 7.3.1	CNA record

References

https://github.com/Kunstmaan/KunstmaanBundlesCMS/security/advisories/GHSA-p279-5wcv-45vqx-refsource-confirm
https://github.com/Kunstmaan/KunstmaanBundlesCMS/commit/1bbdfdeac8e7e91506b1a9271360b9b68d7690d3x-refsource-misc
https://github.com/Kunstmaan/KunstmaanBundlesCMS/releases/tag/7.3.2x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.