CVE-2021-21604 Improper handling of REST API XML deserialization errors in Jenkins

What is CVE-2021-21604?

CVE-2021-21604 is a high-severity unsafe deserialization vulnerability in Jenkins Jenkins, published on 13 Jan 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows attackers with permission to create or configure various objects to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects once discarded by an administrator.

Weakness: CWE-502

Which versions are affected by CVE-2021-21604?

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-2021-21604?

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

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2021-21604 being exploited?

There is no known exploitation of CVE-2021-21604 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-2021-21604, GHSA-qv6f-rcv6-6q3x.