Umbraco Vulnerable to Improper File Access and Credential Exposure through Dictionary Import Functionality

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-66625
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-09 20:15:55 UTC
Updated2026-10-14 21:10:00 UTC
DescriptionUmbraco 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.

Risk And Classification

Primary CVSS: v3.1 4.9 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.003570000 probability, percentile 0.278030000 (date 2026-10-14)

Problem Types: CWE-200 | CWE-377 | CWE-552 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor | CWE-377 CWE-377: Insecure Temporary File | CWE-552 CWE-552: Files or Directories Accessible to External Parties

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.9MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED4.9MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Umbraco Umbraco Cms All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Umbraco Umbraco-CMS affected 10.0.0, < 13.12.1 Not specified

References

ReferenceSourceLinkTags
github.com/umbraco/Umbraco-CMS/commit/7505efd433189037f46547932d4a8b603f... [email protected] github.com Patch
github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-hfv2-pf68-m33x [email protected] github.com Patch, Third Party Advisory
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