CVE-2025-6769: GitLab Information Disclosure Vulnerability

CVE-2025-6769 Overview

CVE-2025-6769 is an information disclosure vulnerability in GitLab Community Edition (CE) and Enterprise Edition (EE). The flaw allows authenticated users to view administrator-only maintenance notes attached to runners by accessing runner details through specific interfaces. The issue is tracked under CWE-497: Exposure of Sensitive System Information to an Unauthorized Control Sphere. GitLab addressed the vulnerability in patch releases 18.1.6, 18.2.6, and 18.3.2. The vulnerability affects all GitLab versions from 15.1 onward prior to the patched releases.

Critical Impact
Any authenticated GitLab user can read administrator-restricted runner maintenance notes, potentially exposing internal infrastructure context, operational notes, or sensitive deployment details.

Affected Products

GitLab CE/EE versions 15.1 through 18.1.5
GitLab CE/EE versions 18.2 through 18.2.5
GitLab CE/EE versions 18.3 through 18.3.1

Discovery Timeline

2025-09-10 - GitLab releases patch versions 18.3.2, 18.2.6, and 18.1.6
2025-09-12 - CVE-2025-6769 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-6769

Vulnerability Analysis

The vulnerability resides in how GitLab exposes runner details to authenticated users. Runners in GitLab can carry maintenance notes intended only for administrators. These notes often describe operational context such as host configuration, scheduled maintenance windows, or internal ownership.

The affected interfaces returned runner detail objects without stripping the administrator-only maintenance_note field before responding to non-administrator sessions. Authenticated users with legitimate access to runner metadata could therefore read content that should have been gated behind the administrator role. The flaw is a broken access control issue mapped to [CWE-497], where sensitive system information crosses an unauthorized control sphere.

Exploitation does not require elevated privileges, user interaction, or chained vulnerabilities. The impact is limited to confidentiality; integrity and availability are not affected.

Root Cause

The root cause is missing authorization enforcement on the maintenance note attribute when runner details are serialized for specific interfaces. The field is intended to be scoped to administrators, but the response serializer did not consistently check the requesting user's role before including it. See GitLab Issue #551957 and the HackerOne Report #3173328 for the vendor-tracked technical discussion.

Attack Vector

An authenticated attacker queries runner detail endpoints or UI views that return runner metadata. The response includes the maintenance_note field even when the caller lacks administrator privileges. The attacker reads the field directly from the response body. No specialized tooling or exploit chain is required beyond a valid GitLab session and knowledge of the relevant runner identifiers.

// No verified exploit code is published for CVE-2025-6769.
// Refer to GitLab Issue #551957 and HackerOne Report #3173328
// for authoritative technical details.

Detection Methods for CVE-2025-6769

Indicators of Compromise

Unusual volume of authenticated requests to runner detail endpoints (for example /api/v4/runners/:id) from non-administrator accounts.
Access patterns where standard developer accounts enumerate runner IDs sequentially or across multiple projects and groups.
API tokens scoped to low-privilege users repeatedly querying runner metadata outside normal CI/CD workflows.

Detection Strategies

Review GitLab production_json.log and api_json.log for requests to runner endpoints by users whose role is not administrator.
Correlate runner detail access with the account's typical project membership to identify out-of-scope reconnaissance.
Alert on API responses to non-admin users that contain the maintenance_note attribute on pre-patch GitLab instances.

Monitoring Recommendations

Forward GitLab application and audit logs to a centralized SIEM and retain for incident review.
Baseline normal runner API traffic per user role and alert on deviations.
Monitor personal access token and project access token usage for anomalous read activity against runner resources.

How to Mitigate CVE-2025-6769

Immediate Actions Required

Upgrade self-managed GitLab instances to 18.3.2, 18.2.6, or 18.1.6 as applicable. GitLab.com is already patched.
Audit existing runner maintenance_note fields and remove any sensitive content such as credentials, internal hostnames, or infrastructure details.
Review audit logs for prior access to runner details by non-administrator accounts since the vulnerable versions were deployed.

Patch Information

GitLab released the fix in the September 10, 2025 patch set. Details are available in the GitLab Patch Release Note for 18.3.2. Upgrade to version 18.3.2, 18.2.6, or 18.1.6 depending on your deployed branch.

Workarounds

No official workaround is documented; upgrading is the supported remediation path.
As an interim measure, clear sensitive content from runner maintenance notes until patching is complete.
Restrict runner creation and administration to a minimal set of accounts to reduce the volume of maintenance notes that could be exposed.

bash

# Verify GitLab version after patching
sudo gitlab-rake gitlab:env:info | grep -i version

# Example upgrade on Omnibus (Debian/Ubuntu)
sudo apt-get update && sudo apt-get install gitlab-ee=18.3.2-ee.0