CVE-2026-26004 Overview
CVE-2026-26004 is an Insecure Direct Object Reference (IDOR) vulnerability affecting Sentry, a popular developer-first error tracking and performance monitoring tool. This cross-organization IDOR flaw exists in Sentry's GroupEventJsonView endpoint, allowing authenticated users to potentially access event data belonging to other organizations.
The vulnerability enables unauthorized access to sensitive error tracking data across organizational boundaries, which could expose application stack traces, error messages, and potentially sensitive debugging information from other tenants on the same Sentry instance.
Critical Impact
Authenticated attackers can exploit improper authorization checks in the GroupEventJsonView endpoint to access error tracking data from organizations they are not authorized to view, potentially exposing sensitive application debugging information and stack traces.
Affected Products
- Sentry versions prior to 26.1.0
Discovery Timeline
- 2026-03-18 - CVE CVE-2026-26004 published to NVD
- 2026-03-18 - Last updated in NVD database
Technical Details for CVE-2026-26004
Vulnerability Analysis
This vulnerability is classified under CWE-639 (Authorization Bypass Through User-Controlled Key), which describes scenarios where an application uses user-supplied input to directly reference database objects without proper authorization validation.
In Sentry's GroupEventJsonView endpoint, the application fails to properly verify that the requesting user has authorization to access event data for the specified organization. This creates a cross-organization data exposure scenario where authenticated users can manipulate object references to access resources belonging to other organizations.
The flaw is particularly significant in multi-tenant deployments where multiple organizations share the same Sentry instance. Error tracking data often contains sensitive information including stack traces, environment variables, request parameters, and application state that could be valuable for reconnaissance or direct exploitation.
Root Cause
The root cause is insufficient authorization checks in the GroupEventJsonView endpoint. While the endpoint validates that a user is authenticated, it fails to properly verify organizational membership before returning event data. This allows authenticated users to bypass tenant isolation controls by directly referencing event identifiers from other organizations.
Attack Vector
The attack is network-based and requires low-privilege authentication. An attacker with valid credentials to any organization on the Sentry instance can exploit this vulnerability by:
- Authenticating to their legitimate Sentry organization
- Identifying or enumerating event group identifiers
- Sending requests to the GroupEventJsonView endpoint with event IDs belonging to other organizations
- Receiving event data that should be restricted to authorized organization members only
The vulnerability requires no user interaction and can be exploited remotely by any authenticated user with access to the Sentry instance.
Detection Methods for CVE-2026-26004
Indicators of Compromise
- Unusual access patterns to the GroupEventJsonView endpoint from authenticated users
- API requests accessing event data outside the user's authorized organization scope
- Elevated API request volumes from individual user accounts to event-related endpoints
- Access log entries showing cross-organization event ID references
Detection Strategies
- Monitor API access logs for requests to /api/0/issues/{issue_id}/events/{event_id}/json/ endpoints with unusual patterns
- Implement alerting for users accessing event data from multiple organization contexts
- Review authentication logs for accounts making bulk requests to event endpoints
- Audit access patterns to identify potential enumeration attempts against event identifiers
Monitoring Recommendations
- Enable detailed logging on Sentry API endpoints, particularly those handling event data
- Configure alerts for anomalous cross-organization access patterns
- Implement rate limiting on event retrieval endpoints to slow enumeration attacks
- Review and audit user access permissions regularly to ensure proper organization boundaries
How to Mitigate CVE-2026-26004
Immediate Actions Required
- Upgrade Sentry to version 26.1.0 or later immediately
- Audit access logs for any suspicious cross-organization data access
- Review and validate organizational access controls
- Consider implementing additional network-level access restrictions to the Sentry API
Patch Information
Sentry has released version 26.1.0 which patches this vulnerability. The fix implements proper authorization validation in the GroupEventJsonView endpoint to ensure users can only access event data from organizations they are explicitly authorized to view.
For detailed patch information, see:
Workarounds
- If immediate upgrade is not possible, consider restricting network access to the Sentry API to trusted IP ranges
- Implement additional proxy-level authorization checks for sensitive API endpoints
- Monitor API access logs closely for suspicious cross-organization access attempts
- Consider temporarily disabling external API access until the patch can be applied
# Verify Sentry version after patching
sentry --version
# Expected: 26.1.0 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
