CVE-2026-1184: Deserialization of Untrusted Data in GitLab

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-14 · updated 2026-06-17
Weakness: CWE-502

Description

GitLab has remediated an issue in GitLab EE affecting all versions from 11.9 before 18.9.7, 18.10 before 18.10.6, and 18.11 before 18.11.3 that could have allowed an unauthenticated user to cause denial of service by uploading a specially crafted file due to improper validation.

Affected products

GitLab: from 11.9.0 before 18.9.7; from 18.10.0 before 18.10.6; from 18.11.0 before 18.11.3 — fixed in 18.10.6, 18.11.3, 18.9.7

How to fix

Upgrade to a fixed version: GitLab 18.10.6, 18.11.3, 18.9.7. Check the vendor advisory for mitigations.

References

https://about.gitlab.com/releases/2026/05/13/patch-release-gitlab-18-11-3-released/
https://gitlab.com/gitlab-org/gitlab/-/work_items/586634
https://hackerone.com/reports/3515842

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