CVE-2026-86479 Overview
CVE-2026-86479 is a missing authorization vulnerability in JetBrains YouTrack, the vendor's issue tracking and project management platform. The flaw allows authenticated attackers to access restricted REST API resources through Insecure Direct Object Reference (IDOR) manipulation. The vulnerability is classified under [CWE-862] Missing Authorization and requires only low-privilege network access to exploit.
Critical Impact
Authenticated attackers can access and modify restricted REST API resources they should not be authorized to view, exposing confidential project data and enabling unauthorized data manipulation across YouTrack tenants.
Affected Products
- JetBrains YouTrack versions before 2026.2.18788
- JetBrains YouTrack versions before 2026.1.14055
- JetBrains YouTrack versions before 2025.3.161254
Discovery Timeline
- 2026-09-07 - CVE-2026-86479 published to NVD
- 2026-09-09 - Last updated in NVD database
Technical Details for CVE-2026-86479
Vulnerability Analysis
The vulnerability resides in JetBrains YouTrack's REST API authorization layer. The API endpoints validate that a caller is authenticated but fail to verify that the authenticated user has permission to access the specific resource identified in the request. Attackers exploit this gap by substituting object identifiers, such as issue IDs, project IDs, or user IDs, in API requests to reach data belonging to other users or projects.
The attack requires network access and valid low-privilege credentials but no user interaction. Successful exploitation compromises confidentiality and integrity of restricted resources without impacting availability.
Root Cause
The root cause is missing authorization checks on REST API resource handlers. YouTrack enforces authentication at the API gateway but does not consistently perform object-level authorization before returning or modifying referenced entities. This design gap is the classic pattern behind Insecure Direct Object Reference vulnerabilities described in [CWE-862].
Attack Vector
An authenticated user sends crafted HTTP requests to REST API endpoints such as /api/issues/{id}, /api/projects/{id}, or related resource paths. By enumerating or guessing identifiers of resources owned by other tenants, projects, or users, the attacker retrieves or modifies data outside their assigned scope. The attack traverses the network at low complexity, and no elevated privileges or victim interaction are required.
No public proof-of-concept code has been verified for CVE-2026-86479. Refer to the JetBrains Security Issue Fixes advisory for vendor-supplied technical details.
Detect Identity Attacks the Moment Authentication Fails
Singularity™ Identity surfaces credential misuse, lateral movement, and privilege escalation in real time, so you can contain the breach before it spreads.
Stop Identity AttacksDetection Methods for CVE-2026-86479
Indicators of Compromise
- Unusual volume of REST API requests from a single authenticated account enumerating sequential resource identifiers on /api/* endpoints.
- HTTP 200 responses to API calls referencing resources outside the caller's assigned projects or teams.
- Access log entries showing a single user session touching a broad range of unrelated issue, project, or user IDs.
Detection Strategies
- Baseline per-user REST API call patterns and alert on deviations, such as sudden access to previously untouched projects or issues.
- Correlate authentication events with authorization outcomes to surface accounts that repeatedly request resources outside their role assignments.
- Deploy web application firewall rules that flag sequential ID enumeration against YouTrack REST API paths.
Monitoring Recommendations
- Forward YouTrack access and audit logs to a centralized analytics platform for behavioral analysis and long-term retention.
- Track REST API response codes and payload sizes per account to detect exfiltration patterns following IDOR access.
- Review privileged and service account activity for anomalous cross-project API access following each YouTrack upgrade window.
How to Mitigate CVE-2026-86479
Immediate Actions Required
- Upgrade YouTrack to version 2026.2.18788, 2026.1.14055, or 2025.3.161254 or later depending on your release branch.
- Audit REST API access logs for anomalous cross-project or cross-user data access preceding the upgrade.
- Rotate any API tokens or personal access tokens that may have been exposed to untrusted users.
Patch Information
JetBrains has released fixed versions across three release branches. Administrators should apply the corresponding patched build for their deployment. Consult the JetBrains Security Issue Fixes page for the authoritative advisory and download links.
Workarounds
- Restrict YouTrack REST API exposure to trusted networks or VPN clients until the patched version is deployed.
- Reduce the population of low-privilege accounts and enforce least-privilege role assignments to shrink the exploitable authenticated attack surface.
- Disable or revoke unused permanent API tokens to limit the number of credentials that could be abused for IDOR enumeration.
# Verify YouTrack version after patching
curl -s -H "Authorization: Bearer <token>" \
https://youtrack.example.com/api/config \
| jq '.version'
# Expected: 2026.2.18788, 2026.1.14055, or 2025.3.161254 (or newer)
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
