Umbraco is an ASP.NET CMS. Due to unsafe handling and deletion of temporary files in versions 10.0.0 through 13.12.0, during the dictionary upload process an attacker with access to the backoffice can trigger predictable requests to temporary file paths. The application’s error responses (HTTP 500 when a file exists, 404 when it does not) allow the attacker to enumerate the existence of arbitrary files on the server’s filesystem. This vulnerability does not allow reading or writing file contents. In certain configurations, incomplete clean-up of temporary upload files may additionally expose the NTLM hash of the Windows account running the Umbraco application. This issue is fixed in version 13.12.1.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/umbraco/Umbraco-CMS/commit/7505efd433189037f46547932d4a8b603fd4a615 Patch
- https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-hfv2-pf68-m33x Patch, Third Party Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 4.9 · umbracoNVD modified 2026-10-14 21:10
Affected (CPE criteria) 1
cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*