CVE-2026-59793 Overview
CVE-2026-59793 is an arbitrary file access vulnerability in JetBrains TeamCity versions prior to 2026.1.2. The flaw resides in the Perforce Version Control System (VCS) integration and allows authenticated attackers to read files outside the intended scope. The issue is classified under CWE-73: External Control of File Name or Path. JetBrains addressed the vulnerability in TeamCity 2026.1.2.
Critical Impact
Authenticated attackers can leverage the Perforce VCS integration to access arbitrary files on the TeamCity server, potentially exposing build secrets, credentials, and source code.
Affected Products
- JetBrains TeamCity versions before 2026.1.2
- TeamCity deployments configured with Perforce VCS integration
- Self-hosted TeamCity build servers
Discovery Timeline
- 2026-07-10 - CVE-2026-59793 published to NVD
- 2026-07-14 - Last updated in NVD database
Technical Details for CVE-2026-59793
Vulnerability Analysis
The vulnerability affects the Perforce VCS integration component of JetBrains TeamCity. TeamCity supports multiple version control backends, including Perforce, allowing build configurations to pull source code from remote repositories. The integration accepts user-controllable path or file name parameters that are not sufficiently validated before being used in file system operations.
An authenticated attacker with permission to configure VCS settings can supply crafted input that causes the server to read files outside the expected repository scope. This exposes contents of the TeamCity server file system to the attacker through the VCS interface or build logs. The impact extends beyond simple disclosure because TeamCity servers frequently store build secrets, deployment credentials, and signing keys.
Root Cause
The root cause aligns with CWE-73, where externally controlled input influences the file path used by the Perforce integration. Insufficient path canonicalization and access checks allow references to files outside the intended directory. The server then returns the file contents without enforcing an appropriate authorization boundary.
Attack Vector
Exploitation requires network access to the TeamCity web interface and low-privilege authenticated access. An attacker configures a Perforce VCS root or modifies parameters interacting with the Perforce integration to reference sensitive files on the server. The resulting file contents flow back through the VCS operation, granting the attacker read access to arbitrary server-side files.
No verified public proof-of-concept code has been released for CVE-2026-59793. Technical details are available in the JetBrains Fixed Issues Summary.
Detection Methods for CVE-2026-59793
Indicators of Compromise
- Unexpected modifications to Perforce VCS root configurations by non-administrative users.
- TeamCity server logs referencing file paths outside configured repository directories, such as /etc/, ../, or absolute paths to system directories.
- Build logs containing file contents unrelated to the source repository being checked out.
- Unusual outbound data volume from TeamCity build agents during VCS synchronization tasks.
Detection Strategies
- Audit the TeamCity teamcity-vcs.log and teamcity-server.log files for path traversal patterns and references to sensitive system paths.
- Review the TeamCity audit log for VCS root creation, modification, and parameter changes performed by non-privileged accounts.
- Correlate authentication events with configuration changes to detect anomalous activity from low-privilege users.
Monitoring Recommendations
- Enable verbose audit logging for VCS configuration changes within TeamCity administrative settings.
- Forward TeamCity logs to a centralized SIEM for retention and correlation with identity and network telemetry.
- Alert on any VCS root parameter values containing directory traversal sequences or references to files outside project directories.
How to Mitigate CVE-2026-59793
Immediate Actions Required
- Upgrade TeamCity to version 2026.1.2 or later, which contains the official fix.
- Inventory all TeamCity instances and identify servers configured with Perforce VCS integration.
- Rotate credentials, API tokens, and signing keys stored on TeamCity servers if compromise is suspected.
- Restrict TeamCity user permissions so only trusted administrators can create or modify VCS roots.
Patch Information
JetBrains released the fix in TeamCity 2026.1.2. Refer to the JetBrains Fixed Issues Summary for the official advisory and release notes. Administrators should apply the upgrade during a planned maintenance window and validate that the Perforce VCS integration continues to function against test projects after upgrading.
Workarounds
- Disable the Perforce VCS integration on TeamCity instances that do not require it until the patch is applied.
- Remove or reduce VCS configuration privileges for accounts that do not require administrative access.
- Place TeamCity servers behind a network segment with restricted access, limiting exposure to trusted build engineers.
- Monitor VCS-related log files for path traversal indicators until upgrade is complete.
# Verify TeamCity server version after upgrade
curl -s -u <admin_user>:<admin_password> \
https://<teamcity-host>/app/rest/server | grep -i version
# Expected output should show version 2026.1.2 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
