CVE-2021-21682 Improper handling of equivalent directory names on Windows in Jenkins

What is CVE-2021-21682?

CVE-2021-21682 is a medium-severity path traversal vulnerability in Jenkins Jenkins, published on 6 Oct 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Jenkins 2.314 and earlier, LTS 2.303.1 and earlier accepts names of jobs and other entities with a trailing dot character, potentially replacing the configuration and data of other entities on Windows.

Which versions are affected by CVE-2021-21682?

5 open source packages ship an affected version, including org.jenkins-ci.main:jenkins-core and jenkins. It affects 1 product.

Products include Jenkins Jenkins.

How do I fix CVE-2021-21682?

Upgrade org.jenkins-ci.main:jenkins-core to a fixed version for your release line: 2.303.2 or 2.315.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2021-21682 being exploited?

There is no known exploitation of CVE-2021-21682 in the wild and no public exploit code.

Other vulnerabilities in Jenkins Jenkins

• CVE-2024-23897 Jenkins Command Line Interface (CLI) Path Traversal Exploited Critical 9.8
• CVE-2018-1000861 Jenkins Stapler Web Framework Deserialization of Untrusted Data Exploited Critical 9.8
• CVE-2017-1000353 Jenkins Remote Code Execution Exploited Critical 9.8
• CVE-2015-5317 Jenkins User Interface (UI) Information Disclosure Exploited High 7.5
• CVE-2021-21690 Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins Critical 9.8

All Jenkins Jenkins vulnerabilities

Sources

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

Also known as BIT-jenkins-2021-21682, GHSA-6q4g-84f3-mw74.