CVE-2026-104890: CWE-434: Unrestricted Upload of File with Dangerous Type in Kunstmaan KunstmaanBundlesCMS
Description
KunstmaanBundlesCMS versions prior to 7.3.2 contain a vulnerability allowing authenticated backend users with media access to upload files with dangerous executable extensions by bypassing a case-sensitive blacklist check. This can lead to remote code execution if the web server executes the uploaded files. The issue is fixed in version 7.3.2.
CVSS v3.1
Score 7.2high
Affected software
Kunstmaan
KunstmaanBundlesCMS
kunstmaan
bundles-cms
kunstmaan
media-bundle
pkg:github/kunstmaan/KunstmaanBundlesCMSRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
KunstmaanBundlesCMS, an open source CMS based on Symfony, has a vulnerability (CWE-434) in versions before 7.3.2 where the file upload blacklist check is case-sensitive. The check occurs in FileHandler::getFilePath but the stored file extension is lowercased afterward. This allows an authenticated backend user with media access to upload files with mixed-case executable extensions (e.g., PHP) that bypass the blacklist and are stored in a web-accessible directory with executable lowercase extensions. The default blacklist also omits several server-executable extensions, increasing the risk of code execution. The vulnerability is addressed in version 7.3.2.
Potential Impact
An authenticated backend user with media access can upload executable files that bypass the blacklist, potentially leading to remote code execution on the web server. This compromises confidentiality, integrity, and availability of the affected system.
Mitigation Recommendations
Upgrade KunstmaanBundlesCMS to version 7.3.2 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-10-02T14:59:11.775Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ac3caa02cdf04f65616ed0d
Added to database: 10/05/2026, 16:04:48 UTC
Last enriched: 10/05/2026, 16:18:12 UTC
Last updated: 10/05/2026, 18:56:34 UTC
Views: 12
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