CVE-2026-100258 in YouTrack
Summary
by MITRE • 09/30/2026
In JetBrains YouTrack before 2026.2.18991 missing authorisation allowed read-only users to read project settings
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in JetBrains YouTrack prior to version 2026.2.18991 represents a critical failure in access control mechanisms, specifically classified under CWE-284 Improper Access Control. This flaw stems from an insufficient authorization check within the application's backend logic, which governs how different user roles interact with project configuration data. In a properly secured environment, read-only users are granted permissions to view issues and perform limited queries but should be explicitly denied access to administrative or structural settings that could alter the workflow or visibility of projects. However, due to this oversight, the system failed to validate whether the requesting entity possessed the necessary elevated privileges before serving sensitive configuration details.
From a technical perspective, the defect likely resides in an API endpoint or server-side handler responsible for retrieving project metadata and settings. When a user with read-only permissions initiates a request to access these specific endpoints, the authentication layer correctly identifies the user's identity but fails at the subsequent authorization step. The application logic does not cross-reference the requested resource type against the user's role-based access control list effectively. This allows an attacker or malicious insider operating under a restricted account to bypass intended restrictions and extract detailed project configurations. Such data often includes workflow rules, field definitions, permission schemes for other users, and potentially integration tokens or webhook URLs that are not meant to be exposed to non-administrative staff.
The operational impact of this vulnerability is significant in terms of information disclosure and potential downstream exploitation. While the immediate action is limited to reading settings rather than modifying them, the exposure of project configurations can facilitate further attacks. For instance, knowledge of internal workflow structures or permission schemes allows an attacker to map out the security posture of a team more accurately. This intelligence could be used to craft social engineering campaigns that appear legitimate based on real organizational processes. Furthermore, if the exposed settings include details about third-party integrations or API keys stored in configuration files accessible through this vector, it could lead to credential theft and unauthorized access to external services connected to YouTrack. In a corporate environment where multiple teams share instances of YouTrack, this breach compromises data isolation between projects that rely on strict role separation for compliance purposes.
This incident aligns with the MITRE ATT&CK framework under techniques related to Discovery, specifically T1087 Account Discovery or T1526 Cloud Service Discovery, as it involves enumerating system configurations through unauthorized means. It also reflects common patterns found in CWE-639 Authorization Bypass Through User-Controlled Key if the vulnerability involved manipulating identifiers, though here it is a broader failure of role-based checks. The root cause highlights the importance of implementing defense-in-depth strategies where every sensitive operation undergoes rigorous permission validation regardless of how simple or read-only the action appears to be.
To mitigate this risk and prevent similar occurrences in future releases, JetBrains has addressed the authorization logic by ensuring that all endpoints returning project settings enforce strict role-based access controls. Administrators should immediately update their YouTrack instances to version 2026.2.18991 or later to patch this vulnerability. In environments where immediate upgrading is not feasible due to operational constraints, organizations can implement network-level security measures such as Web Application Firewalls configured to monitor for anomalous access patterns by read-only users attempting to reach administrative endpoints. Additionally, regular audits of user permissions and role assignments are recommended to ensure that the principle of least privilege is strictly enforced across all project spaces within the instance.