Third-party access via protected-branch ID token spoofing
Published Aug 13, 2025 · Updated Aug 29, 2025
Authorization bypass in GitLab CE/EE allows remote authenticated users to obtain protected-branch ID tokens through forked merge requests. Cross-project merge request pipelines build ID-token project and ref claims from the target project rather than the fork source, so an attacker-controlled job receives the trusted protected-branch subject. Developer access, a protected target branch, and a relying service that trusts branch-scoped GitLab OIDC claims are required; the token grants that service's protected-branch permissions.
Summary
What happened
Authorization bypass in GitLab CE/EE allows remote authenticated users to obtain protected-branch ID tokens through forked merge requests. Cross-project merge request pipelines build ID-token project and ref claims from the target project rather than the fork source, so an attacker-controlled job receives the trusted protected-branch subject. Developer access, a protected target branch, and a relying service that trusts branch-scoped GitLab OIDC claims are required; the token grants that service's protected-branch permissions.
The record
- CVE
- CVE-2025-5819
- Published
- Aug 13, 2025
- Updated
- Aug 29, 2025
- Vendor
- GitLab
- Product
- GitLab
- Classifications
- CWE-732, T1550.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 13, 2025CVE publishedPublication date reported by the CVE source.
- Aug 29, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=15.7 <18.0.6
- Affected versionversion=18.1 <18.1.4
- Affected versionversion=18.2 <18.2.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Forked merge-request protected-branch token reproducerproof of concept · demonstrated
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Technologies
Your stack
See the directory against your own environment.
Your stack
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