CVE-2026-103494 in YouTrack
Summary
by MITRE • 10/01/2026
In JetBrains YouTrack before 2026.2.19422 privilege escalation was possible via user group membership changes
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in JetBrains YouTrack prior to version 2026.2.19422 represents a critical authorization flaw that allows for unauthorized privilege escalation through the manipulation of user group memberships. This issue stems from an insufficiently enforced access control mechanism within the application's administrative interface and underlying API endpoints responsible for managing organizational structure and user roles. In secure software architecture, changes to high-privilege entities such as administrator groups or project owners must be subject to rigorous validation checks that verify not only the identity of the requesting user but also their explicit authorization rights to perform such modifications on specific target accounts. The flaw in YouTrack indicates a breakdown in this verification process, where the system fails to adequately validate whether the initiating requestor possesses the necessary administrative privileges or if they are attempting to modify groups outside their scope of authority.
From a technical perspective, this vulnerability aligns with CWE-269, which classifies Improper Privilege Control. The root cause likely involves an insecure direct object reference (IDOR) pattern or a failure in server-side access control checks when processing requests related to group membership updates. An attacker who has obtained valid credentials for a standard user account can exploit this logic error by crafting specific HTTP requests that alter the membership of privileged groups, such as adding their own low-privilege account to an administrator group or transferring ownership of critical projects to themselves. Because YouTrack is often used in enterprise environments where it serves as the central hub for issue tracking, project management, and collaboration, the ability to escalate privileges effectively grants the attacker full control over the instance. This includes the ability to view sensitive data, modify workflows, delete records, or install malicious plugins that could compromise the broader infrastructure connected to the YouTrack server.
The operational impact of this vulnerability is severe due to its direct correlation with ATT&CK technique T1078, Valid Accounts, and specifically T1098, Account Manipulation. By leveraging this flaw, an adversary can establish persistence within the system without needing to exploit a separate authentication bypass or credential theft vector beyond initial low-level access. Once elevated privileges are achieved, the attacker gains unrestricted read and write access to all projects hosted on the instance. This compromises the confidentiality of intellectual property stored in issue descriptions, attachments, and comments. Furthermore, it undermines the integrity of the development process by allowing unauthorized changes to project configurations, workflow states, and user permissions. In a DevOps context where YouTrack might be integrated with CI/CD pipelines or other automated tools via API keys associated with privileged accounts, this escalation could lead to broader system compromise, including remote code execution if malicious webhooks or integrations are configured by the attacker.
Mitigation for this vulnerability requires immediate action from system administrators and security teams responsible for JetBrains YouTrack deployments. The primary remediation step is to upgrade all affected instances to version 2026.2.19422 or later, where the access control logic has been corrected to enforce strict validation on group membership changes. For organizations unable to patch immediately due to operational constraints, temporary mitigations should include restricting network access to the YouTrack administrative interface and API endpoints to only trusted IP addresses and administrators. Additionally, implementing multi-factor authentication for all user accounts adds a layer of defense against credential-based attacks that might precede this privilege escalation. Security monitoring tools should be configured to alert on anomalous changes in group memberships or sudden increases in permission levels for standard users, providing an early warning indicator of potential exploitation attempts. Regular audits of administrative privileges and adherence to the principle of least privilege are essential long-term strategies to minimize the risk surface associated with such authorization flaws.