Summary
Jenkins 2.286 and earlier, LTS 2.277.1 and earlier does not properly check that a newly created view has an allowed name. When a form to create a view is submitted, the name is included twice in the submission. One instance is validated, but the other instance is used to create the value.
This allows attackers with View/Create permission to create views with invalid or already-used names.
Jenkins 2.287, LTS 2.277.2 uses the same submitted value for validation and view creation.
Impact
CVE-2021-21640 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.287, 2.277.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
org.jenkins-ci.main:jenkins-core to 2.287 or later; org.jenkins-ci.main:jenkins-core to 2.277.2 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-21640? CVE-2021-21640 is a medium-severity security vulnerability in org.jenkins-ci.main:jenkins-core (maven), affecting versions >= 2.278, <= 2.286. It is fixed in 2.287, 2.277.2.
- How severe is CVE-2021-21640? CVE-2021-21640 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.jenkins-ci.main:jenkins-core are affected by CVE-2021-21640? org.jenkins-ci.main:jenkins-core (maven) versions >= 2.278, <= 2.286 is affected.
- Is there a fix for CVE-2021-21640? Yes. CVE-2021-21640 is fixed in 2.287, 2.277.2. Upgrade to this version or later.
- Is CVE-2021-21640 exploitable, and should I be worried? Whether CVE-2021-21640 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-21640 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-21640?
- Upgrade
org.jenkins-ci.main:jenkins-coreto 2.287 or later - Upgrade
org.jenkins-ci.main:jenkins-coreto 2.277.2 or later
- Upgrade