CVE-2026-123329 in YouTrack
Summary
by MITRE • 11/06/2026
In JetBrains YouTrack before 2026.2.19562 missing authorization in TeamCity integration allowed disclosure of other projects' actions
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Analysis
by VulDB Data Team • 11/06/2026
The vulnerability identified in JetBrains YouTrack prior to version 2026.2.19562 represents a critical failure in access control mechanisms within the platform's integration with JetBrains TeamCity, an integrated development environment and continuous integration server. This flaw specifically manifests as missing authorization checks when handling requests related to team or project synchronization between the two systems. In a properly secured architecture, any operation that retrieves, modifies, or displays data from one system based on triggers from another must strictly validate that the initiating user possesses sufficient privileges for the target resource within both contexts. However, in this instance, the integration endpoint failed to enforce these necessary permissions checks, effectively bypassing the standard authentication and authorization layers designed to isolate project boundaries.
From a technical perspective, the core issue lies in the logic governing how YouTrack processes events or data pulls initiated by TeamCity. When TeamCity sends information regarding build statuses, commits, or other actions associated with specific projects, YouTrack's integration module accepted these inputs without verifying whether the user account linked to that TeamCity instance had explicit permission to view or interact with the corresponding project in YouTrack. This architectural oversight allows an attacker who has access to a lower-privileged TeamCI account, or potentially one that can be manipulated through other means such as credential theft or social engineering, to query and retrieve sensitive information from unrelated projects within YouTrack. The vulnerability essentially creates a horizontal privilege escalation path where lateral movement across project boundaries becomes possible without proper validation of user rights against the target resource's access control list.
The operational impact of this vulnerability is significant for organizations relying on strict data isolation between different development teams or client projects hosted within the same YouTrack instance. Disclosure of other projects' actions can lead to the exposure of sensitive intellectual property, including source code references, bug reports containing proprietary logic details, release schedules, and internal communication threads that were intended to be private to specific groups. For security-conscious enterprises, this breach undermines the fundamental principle of least privilege and compromises the confidentiality integrity required for secure software development lifecycles. Attackers could use this information to map out an organization's infrastructure, identify high-value targets for further exploitation, or gather intelligence to craft more sophisticated phishing campaigns targeting employees involved in those exposed projects.
This vulnerability aligns with CWE-284 Improper Access Control and specifically relates to CWE-862 Missing Authorization, as the system failed to enforce required access rights during a critical operation. In terms of offensive security frameworks, this behavior is consistent with techniques found under MITRE ATT&CK ID T1078 Valid Accounts, where an attacker leverages legitimate credentials to move laterally and gather information from unauthorized resources within a networked environment. The lack of proper authorization checks in the integration layer effectively turns a trusted administrative or development tool into a vector for data exfiltration across organizational silos that should remain isolated.
To mitigate this risk, organizations must immediately upgrade their JetBrains YouTrack instances to version 2026.2.19562 or any later release where these authorization checks have been rigorously implemented and tested by the vendor. Until an upgrade is feasible, administrators should consider disabling the TeamCity integration if it is not strictly necessary for current operations, thereby removing the attack vector entirely. Additionally, reviewing audit logs for unusual patterns of data access from TeamCI-linked accounts can help identify potential exploitation attempts that may have occurred prior to remediation. It is also advisable to conduct a comprehensive review of all third-party integrations within YouTrack to ensure they adhere to strict authorization protocols and do not expose similar vulnerabilities in other connected services. Regular security assessments and penetration testing focused on integration points between disparate systems are essential for maintaining robust access control postures in complex development environments.