CVE-2026-100262 in YouTrack
Summary
by MITRE • 09/30/2026
In JetBrains YouTrack before 2026.2.18991 missing authorisation allowed users with read-only project access to overwrite project notification templates
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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 the application's authorization logic, specifically concerning the management of project-level configuration objects. This flaw allows users who possess only read-only permissions for specific projects to perform write operations on notification templates associated with those same projects. In enterprise environments where YouTrack is deployed as a central issue tracking and workflow automation platform, such permission boundaries are fundamental to maintaining data integrity and operational security. The absence of proper access control checks enables unauthorized modification of system-critical settings that dictate how stakeholders are alerted about project activities, thereby undermining the principle of least privilege.
From a technical perspective, this vulnerability stems from an insufficient verification mechanism within the backend API endpoints responsible for updating notification template configurations. When a user submits a request to modify these templates, the application fails to adequately validate whether the requesting entity holds write privileges or administrative rights over the target project. Instead, it appears to rely on broader session context or incorrectly cached permission states that do not reflect the granular read-only restrictions applied at the project level. This logic error permits authenticated users with limited access scopes to bypass intended security controls and alter configuration data that should be immutable to their role. The flaw is particularly insidious because notification templates are often used for automated workflows, meaning an attacker can inject malicious content or disrupt communication channels without triggering immediate alarms from standard audit logs focused on issue creation or modification rather than system configuration changes.
The operational impact of this vulnerability extends beyond simple unauthorized access and touches upon the reliability and security of organizational communications. By overwriting notification templates, a compromised account with read-only rights could alter email subjects, body content, or recipient lists associated with project events. This capability can be leveraged for phishing attacks where malicious actors craft deceptive notifications that appear to originate from legitimate YouTrack workflows, potentially tricking other users into clicking harmful links or providing credentials. Furthermore, the ability to disrupt notification delivery by deleting critical templates can lead to significant operational delays, as team members may miss important updates regarding bug fixes, security patches, or project milestones. In regulated industries where audit trails and communication integrity are mandatory for compliance, such unauthorized modifications constitute a severe violation of data governance standards.
This issue aligns with CWE-269, which describes Improper Privilege Control, specifically highlighting the failure to enforce proper authorization checks before allowing state-changing operations. It also maps closely to MITRE ATT&CK technique T1078, Valid Accounts, where adversaries use legitimate credentials that have been granted insufficient privileges but are exploited due to misconfiguration or logic flaws to achieve higher-level objectives such as configuration tampering. The vulnerability underscores the importance of rigorous input validation and strict enforcement of role-based access control (RBAC) policies within web applications handling sensitive organizational data.
To mitigate this risk, organizations must immediately upgrade their JetBrains YouTrack instances to version 2026.2.18991 or later, where these authorization checks have been corrected. Until the patch is applied, administrators should review user permissions and restrict access to notification template settings exclusively to users with explicit administrative rights for each project. Additionally, implementing network-level monitoring can help detect anomalous patterns of configuration changes originating from accounts that typically exhibit only read-only behavior. Regular audits of permission assignments and continuous validation of RBAC implementations are essential practices to prevent similar privilege escalation or unauthorized modification vulnerabilities in the future.