CVE-2025-27601
📋 TL;DR
An improper API access control vulnerability in Umbraco CMS allows authenticated users with low privileges to create and update data type information, which should be restricted to users with settings section access. This affects Umbraco installations using the API management package before versions 15.2.3 and 14.3.3. The vulnerability enables unauthorized data manipulation within the CMS.
💻 Affected Systems
- Umbraco CMS
📦 What is this software?
Umbraco Cms by Umbraco
Umbraco Cms by Umbraco
⚠️ Risk & Real-World Impact
Worst Case
Low-privilege attackers could modify critical data type configurations, potentially disrupting content management functionality or enabling further privilege escalation.
Likely Case
Unauthorized users modify data type settings, causing content display issues or configuration inconsistencies.
If Mitigated
Proper access controls prevent unauthorized data type modifications, maintaining system integrity.
🎯 Exploit Status
Exploitation requires authenticated low-privilege user credentials; no public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 15.2.3 and 14.3.3
Vendor Advisory: https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-6ffg-mjg7-585x
Restart Required: Yes
Instructions:
1. Backup your Umbraco installation and database. 2. Update Umbraco to version 15.2.3 (for v15) or 14.3.3 (for v14). 3. Restart the application server. 4. Verify the update was successful.
🧯 If You Can't Patch
- Restrict low-privilege user access to the Umbraco admin interface.
- Implement network segmentation to isolate Umbraco instances from untrusted networks.
🔍 How to Verify
Check if Vulnerable:
Check Umbraco version in admin dashboard or via package manager; versions before 15.2.3 (v15) or 14.3.3 (v14) are vulnerable.Check Version:
Check via Umbraco admin dashboard at Settings > Updates or examine web.config/package.config files.Verify Fix Applied:
Confirm Umbraco version is 15.2.3 or higher (v15) or 14.3.3 or higher (v14) after update.📡 Detection & Monitoring
Log Indicators:
- Unusual data type creation/modification events by low-privilege users in Umbraco audit logs.
- API calls to data type endpoints from unauthorized user accounts.
Network Indicators:
- HTTP POST/PUT requests to Umbraco API data type endpoints from low-privilege user sessions.
SIEM Query:
source="umbraco_logs" AND (event_type="data_type_modified" OR event_type="data_type_created") AND user_role="low_privilege"