Listen to this Post
In JetBrains TeamCity versions prior to 2026.1, a critical vulnerability (CVE-2026-49374) has been identified due to improper permission checks. This flaw allows unauthorized users to access sensitive build configuration parameters, which may include database credentials, API keys, and other confidential build artifacts. The vulnerability arises at the application layer where user authentication and authorization checks fail to properly validate whether a requesting user possesses sufficient privileges to access specific build configuration data. By crafting requests that bypass intended access restrictions, even users with minimal permissions can exploit the system to retrieve confidential information. This operation can be performed remotely, making the attack surface highly exposed. The issue aligns with CWE-285 (Improper Authorization) and maps to ATT&CK techniques T1566 (Credential Harvesting) and T1071 (Application Layer Protocol). Organizations using affected TeamCity versions are urged to upgrade to version 2026.1 or later, which contains the necessary permission validation fixes.
DailyCVE Form:
Platform: JetBrains TeamCity
Version: prior 2026.1
Vulnerability: improper permission checks
Severity: Critical
Date: May 29, 2026
Prediction: patch within days
What Undercode Say:
Identify vulnerable TeamCity instances curl -s http://teamcity-server/admin/diagnostic.html?diagnosticType=info | grep "Version" Query REST API for unauthorized parameter access curl -k -X GET "https://teamcity-server/app/rest/builds/id:1/parameters" -H "Authorization: Bearer <victim_token>" Check permissions for a specific user curl -k -X GET "https://teamcity-server/app/rest/users/user:username/permissions" -H "Authorization: Bearer <admin_token>"
Exploit:
A remote attacker with low-privileged access can send crafted requests to the TeamCity REST API, bypassing authorization controls and retrieving sensitive build parameters. The exploit leverages improper validation in the parameter access endpoint, allowing unauthorized disclosure of secrets. This can lead to privilege escalation and further compromise of the CI/CD pipeline.
Protection:
- Upgrade to JetBrains TeamCity version 2026.1 or later immediately.
- Implement network segmentation and strict firewall rules to limit access to the TeamCity server.
- Conduct thorough access control reviews to align user permissions with operational requirements.
- Regularly monitor logs for suspicious REST API calls.
Impact:
Successful exploitation exposes sensitive configuration data, enabling credential theft, unauthorized code deployment, and complete compromise of the build infrastructure. Attackers can leverage extracted information for social engineering and downstream attacks, potentially leading to a full supply chain breach.
🎯Let’s Practice Exploiting & Learn Patching For Free:
🎓 Live Courses & Certifications:
Join Undercode Academy for Verified Certifications
🚀 Request a Custom Project:
Secure, high-velocity infrastructure and disruptive technological engineering. Contact our engineering team for high-tier development and proprietary systems:
[email protected]
💎 Smart Architecture | 🛡️ Secure by Design | ⭐ Trusted by Thousands
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
