Unauthenticated service hang via oversized SAML responses
Published Sep 12, 2025 · Updated Sep 12, 2025
Denial of service in GitLab CE/EE before 18.1.6, 18.2.6, or 18.3.2 allows remote attackers to make an instance unresponsive. Its SAML response handling accepts multiple concurrent oversized responses without an effective quantity limit, consuming enough resources to deny legitimate requests. No account is required, but the affected code path must be reachable through a SAML-enabled instance; GitLab has not disclosed the exhausted resource or exact handler.
Summary
What happened
Denial of service in GitLab CE/EE before 18.1.6, 18.2.6, or 18.3.2 allows remote attackers to make an instance unresponsive. Its SAML response handling accepts multiple concurrent oversized responses without an effective quantity limit, consuming enough resources to deny legitimate requests. No account is required, but the affected code path must be reachable through a SAML-enabled instance; GitLab has not disclosed the exhausted resource or exact handler.
The record
- CVE
- CVE-2025-2256
- Published
- Sep 12, 2025
- Updated
- Sep 12, 2025
- Vendor
- GitLab
- Product
- GitLab
- Classifications
- CWE-1284, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 12, 2025CVE publishedPublication date reported by the CVE source.
- Sep 12, 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=18.2 <18.2.6
- Affected versionversion=18.3 <18.3.2
- Affected versionversion=7.12 <18.1.6
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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