CVE-2021-21609 Missing permission check for paths with specific prefix in Jenkins

What is CVE-2021-21609?

CVE-2021-21609 is a medium-severity missing authorization vulnerability in Jenkins Jenkins, published on 13 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not correctly match requested URLs to the list of always accessible paths, allowing attackers without Overall/Read permission to access some URLs as if they did have Overall/Read permission.

Weakness: CWE-863

Which versions are affected by CVE-2021-21609?

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-2021-21609?

Upgrade org.jenkins-ci.main:jenkins-core to a fixed version for your release line: 2.263.2 or 2.275.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2021-21609 being exploited?

There is no known exploitation of CVE-2021-21609 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-2021-21609, GHSA-4625-q52w-39cx.