CVE-2021-39940 Denial of service in GitLab

What is CVE-2021-39940?

CVE-2021-39940 is a medium-severity denial of service vulnerability in Gitlab Gitlab, published on 13 Dec 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 13.2 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. GitLab Maven Package registry is vulnerable to a regular expression denial of service when a specifically crafted string is sent.

Weakness: CWE-1333

Which versions are affected by CVE-2021-39940?

1 open source package ship an affected version, including gitlab. It affects 1 product.

Products include Gitlab Gitlab.

How do I fix CVE-2021-39940?

Upgrade gitlab to a fixed version for your release line: 14.3.6, 14.4.4 or 14.5.2.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-39940 being exploited?

There is no known exploitation of CVE-2021-39940 in the wild and no public exploit code.

Other vulnerabilities in Gitlab Gitlab

• CVE-2026-97229 GitLab Community Edition and Enterprise Edition Integer Overflow or Wraparound Exploited Critical 10.0
• CVE-2026-85706 GitLab Community Edition and Enterprise Edition Path Traversal Exploited Critical 10.0
• CVE-2023-7028 GitLab Community and Enterprise Editions Improper Access Control Exploited Critical 10.0
• CVE-2021-22205 GitLab Community and Enterprise Editions Remote Code Execution Exploited Critical 10.0
• CVE-2021-39935 GitLab Community and Enterprise Editions Server-Side Request Forgery (SSRF) Exploited Medium 6.8

All Gitlab Gitlab vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-gitlab-2021-39940, GHSA-762x-jmwj-7xmj, UBUNTU-CVE-2021-39940.