CVE-2021-21684 Stored XSS vulnerability in Jenkins Git Plugin

What is CVE-2021-21684?

CVE-2021-21684 is a medium-severity cross-site scripting vulnerability in Jenkins Git Plugin, published on 6 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Jenkins Git Plugin 4.8.2 and earlier does not escape the Git SHA-1 checksum parameters provided to commit notifications when displaying them in a build cause, resulting in a stored cross-site scripting (XSS) vulnerability.

Weakness: CWE-116

Which versions are affected by CVE-2021-21684?

2 open source packages ship an affected version, including org.jenkins-ci.plugins:git. It affects 1 product.

Products include Jenkins Git.

How do I fix CVE-2021-21684?

Upgrade org.jenkins-ci.plugins:git to 4.8.3 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-21684 being exploited?

There is no known exploitation of CVE-2021-21684 in the wild and no public exploit code.

Other vulnerabilities in Jenkins Git Plugin

• CVE-2022-36882 Lack of authentication mechanism in Jenkins Git Plugin webhook High 8.8
• CVE-2022-36883 Lack of authentication mechanism in Jenkins Git Plugin webhook High 7.5
• CVE-2022-30947 Path traversal in Jenkins Git Mercurial and Repo Plugins High 7.5
• CVE-2017-1000092 Cross-Site Request Forgery in Jenkins Git Plugin High 7.5
• CVE-2022-38663 Improper masking of credentials Jenkins in Git Plugin Medium 6.5

Sources

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

Also known as GHSA-gghc-g8cj-4vfv.