CVE-2026-12910

Analyzed Analyzed - Analysis Complete

Authentication Bypass in GitLab CE/EE via SAML SSO

Publication date: 2026-09-15

Last updated on: 2026-09-28

Assigner: GitLab Inc.

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.6 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2 that under certain conditions could have allowed an authenticated user to bypass SAML SSO sign-in restrictions and authenticate without SSO due to missing authentication enforcement checks.

CVSS Scores

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Meta Information

Published

2026-09-15

Last Modified

2026-09-28

Generated

2026-10-06

AI Q&A

2026-09-15

EPSS Evaluated

2026-10-04

NVD

CVE-2026-12910

EUVD

EUVD-2026-78909

Affected Vendors & Products

Vendor	Product	Version / Range
gitlab	gitlab	From 19.2.0 (inc) to 19.2.6 (exc)
gitlab	gitlab	From 19.3.0 (inc) to 19.3.2 (exc)
gitlab	gitlab	From 19.2.0 (inc) to 19.2.6 (exc)
gitlab	gitlab	From 19.3.0 (inc) to 19.3.2 (exc)
gitlab	gitlab	From 18.6.0 (inc) to 19.1.8 (exc)
gitlab	gitlab	From 18.6.0 (inc) to 19.1.8 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-306	The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

Executive Summary

This vulnerability in GitLab CE/EE allows an authenticated user to bypass SAML SSO sign-in restrictions and authenticate without SSO due to missing authentication enforcement checks. It affects versions from 18.6 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2.

Detection Guidance

This vulnerability involves missing SAML SSO sign-in restrictions in GitLab. To detect it, check GitLab server logs for authentication events where users bypassed SSO. Look for logs indicating successful logins without SAML assertions. Verify if users authenticated without SAML by reviewing access logs and authentication records.

Impact Analysis

An attacker could exploit this to bypass intended SSO restrictions, potentially gaining unauthorized access to sensitive data or systems if SAML SSO is enforced for security.

Compliance Impact

This vulnerability could allow an authenticated user to bypass SAML SSO sign-in restrictions, potentially enabling unauthorized access to sensitive data. This may impact compliance with GDPR and HIPAA by increasing the risk of data breaches and unauthorized disclosures, as SSO enforcement is a key control for access management.

Mitigation Strategies

Update GitLab CE/EE to version 19.1.8, 19.2.6, or 19.3.2 or later to address the missing SAML SSO authentication enforcement checks.

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