Description
An issue has been discovered in GitLab CE/EE affecting all versions from 7.12 before 18.1.6, 18.2 before 18.2.6, and 18.3 before 18.3.2 that could have allowed unauthorized users to render the GitLab instance unresponsive to legitimate users by sending multiple concurrent large SAML responses.
Affected products
gitlab: gitlab
References3
- about.gitlab.com/releases/2025/09/10/patch-release-gitlab-18-3-… Release NotesVendor Advisory
- gitlab.com/gitlab-org/gitlab/-/issues/524633 Broken Link
- hackerone.com/reports/3019485 Permissions Required
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 45 · as of 8 November 2026
- CWE
- CWE-1284
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.