Description

In JetBrains YouTrack before 2026.2.18634 improper permission checks allowed read-only users to create and modify whiteboard cards

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-09-07T17:17:27.627Z",
  "pubdate": "2026-09-07T17:17:27.627Z",
  "executiveSummary": "This vulnerability involves an improper authorization flaw within the JetBrains YouTrack whiteboard feature. The security defect allows users assigned with read-only permissions to perform unauthorized write operations, specifically the creation and modification of whiteboard cards.\nThe vulnerability affects JetBrains YouTrack versions prior to 2026.2.18634. By bypassing mandatory access control checks, low-privileged users can manipulate data within the whiteboard interface, potentially leading to unauthorized information disclosure, data integrity degradation, or the introduction of malicious content into project planning spaces.\nThe flaw stems from a failure to consistently enforce permission scopes on the backend during whiteboard transaction requests. Since read-only users are erroneously granted the capability to trigger state-changing actions, the attack surface expands to include any authenticated user, regardless of their intended role restriction. There are no known requirements for complex exploit chains; the vulnerability is exploitable through standard application interaction by any user possessing basic read-only access. Organizations relying on strict segregation of duties for project management and planning are at the highest risk of unauthorized data modification.",
  "technicalDetails": "The root cause of this vulnerability lies in an insufficient implementation of server-side access control checks within the whiteboard module of JetBrains YouTrack. When a user initiates a request to create or update a card on a whiteboard, the application's underlying authorization logic fails to validate whether the requester possesses the 'Update' or 'Create' permissions required for such entities.\nUnder normal operating conditions, the YouTrack permission model should restrict users with read-only access to 'GET' operations, prohibiting 'POST', 'PUT', or 'PATCH' methods targeting card state modification. In the vulnerable versions, the backend API endpoints responsible for whiteboard card lifecycle management fail to consult the security context of the session before processing the request payload. Consequently, these endpoints treat input from read-only users as authorized traffic.\nThe attack flow follows a predictable pattern: 1) The attacker authenticates to the YouTrack instance with a valid read-only account. 2) The attacker accesses a whiteboard interface. 3) Utilizing the browser's developer tools or a manual API proxy, the attacker intercepts the JSON payload sent during a card creation or modification event. 4) The application, failing to perform a secondary authorization check at the controller level, processes the request and commits the changes to the database. This allows the read-only user to inject, modify, or delete whiteboard data, effectively bypassing the intended organizational security policy.\nThe vulnerable component is the whiteboard service backend, which serves as the interface between the client-side UI and the primary database. Because the vulnerability exists at the logic level rather than the client-side interface, masking elements in the UI is insufficient to prevent exploitation. Any actor with access to the authenticated network path and a read-only credential can perform these actions. The post-exploitation impact includes the potential to disrupt team coordination, alter project statuses, or leverage the whiteboard as a vector for social engineering by injecting misleading information into a trusted project management environment."
}