CVE-2026-100271 in YouTrack
Summary
by MITRE • 09/30/2026
In JetBrains YouTrack before 2026.2.19197 missing authorisation on several endpoints allowed authenticated users to access information from other projects
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in versions of JetBrains YouTrack prior to build 2026.2.19197 represents a critical failure in the application's authorization logic, specifically classified under CWE-862 which denotes Missing Authorization. This flaw allows authenticated users to bypass intended access controls and retrieve sensitive data belonging to other projects within the same instance. In enterprise environments where YouTrack is deployed as a central hub for project management and issue tracking, such an oversight can lead to significant information disclosure incidents. The core technical deficiency lies in the server-side validation of user permissions when processing requests directed at specific API endpoints or web interfaces. Instead of verifying that the requesting user possesses explicit rights to view the target resource based on their role and membership within a particular project scope, the application relies on insufficient checks or fails to enforce isolation boundaries between distinct projects.
From an operational perspective, this vulnerability enables horizontal privilege escalation where users can access data they are not authorized to see simply by manipulating request parameters such as issue IDs or project identifiers. An attacker with valid credentials for one project could iterate through known or guessed identifiers to extract details from unrelated projects. This includes viewing bug reports, feature requests, sprint plans, and potentially confidential business logic documented within those issues. The impact extends beyond mere data leakage; it compromises the integrity of collaborative workflows by allowing unauthorized modifications if write permissions are similarly affected, although the primary reported risk is information disclosure. Such exposure can violate organizational security policies, compliance requirements like GDPR or HIPAA depending on the nature of the stored data, and erode trust among team members who expect their project-specific work to remain isolated from other departments or teams.
The attack vector for this vulnerability aligns with ATT&CK technique T1078 which involves Valid Accounts being used by adversaries to gain initial access and maintain persistence within a system. Since the attacker must be authenticated, it highlights that strong authentication alone is insufficient without robust authorization controls. The exploitation typically requires no special privileges beyond standard user status, making it accessible to any insider threat or compromised account with low-level permissions. This underscores the importance of implementing principle of least privilege in application design and ensuring that every state-changing query and data retrieval operation undergoes rigorous permission validation against the current session's context.
To mitigate this risk, organizations running affected versions must immediately upgrade to JetBrains YouTrack version 2026.2.19197 or later where these authorization checks have been corrected. Until an upgrade is feasible, administrators should review access logs for unusual patterns of data retrieval across multiple projects and restrict network-level access to the application if possible. It is also advisable to audit user roles and permissions regularly to ensure that no excessive privileges are granted unnecessarily. Future development cycles should incorporate automated security testing focused on broken object level authorization flaws to detect similar gaps before deployment, ensuring that all endpoints enforce strict context-aware permission checks consistent with industry best practices for secure web application architecture.