CVE-2021-21610: Jenkins core Cross-Site Scripting Vulnerability
MODERATECVE-2021-21610 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Jenkins core libraries in the Maven ecosystem. The issue involves reflected xss vulnerability in jenkins markup formatter preview. Remediation is available by upgrading affected packages to version 2.263.2, 2.275.
CVE-2021-21610 at a Glance
Security Impact
CVSS: 6.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).
How to Fix CVE-2021-21610
To remediate this vulnerability, upgrade all affected Jenkins core dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>org.jenkins-ci.main</groupId>
<artifactId>jenkins-core</artifactId>
<version>2.263.2</version>
</dependency><dependency>
<groupId>org.jenkins-ci.main</groupId>
<artifactId>jenkins-core</artifactId>
<version>2.275</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=org.jenkins-ci.mainHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2021-21610, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=org.jenkins-ci.mainAnalyze the terminal output to locate any version of Jenkins core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.263.2), your application is affected.
Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.main command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Jenkins core, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-21610 Affected Jenkins core Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
< 2.263.2
|
2.263.2
|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
≥ 2.264
< 2.275
|
2.275
|
References
Frequently Asked Questions
What is CVE-2021-21610?
Which Jenkins core versions are affected?
What version fixes CVE-2021-21610?
Is jenkins-core affected?
What is the CVSS score of CVE-2021-21610?
What CWE is associated with CVE-2021-21610?
How can I check Maven dependencies for CVE-2021-21610?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-7qf3-c2q8-69m3",
"modified" : "2023-10-27T13:25:22Z",
"published" : "2022-05-24T17:39:13Z",
"aliases" : [ "CVE-2021-21610" ],
"summary" : "Reflected XSS vulnerability in Jenkins markup formatter preview",
"details" : "Jenkins allows administrators to choose the markup formatter to use for descriptions of jobs, builds, views, etc. displayed in Jenkins. When editing such a description, users can choose to have Jenkins render a formatted preview of the description they entered.\n\nJenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering the formatted preview of markup passed as a query parameter. This results in a reflected cross-site scripting (XSS) vulnerability if the configured markup formatter does not prohibit unsafe elements (JavaScript) in markup, like [Anything Goes Formatter Plugin](https://plugins.jenkins.io/anything-goes-formatter/).\n\nJenkins 2.275, LTS 2.263.2 requires that preview URLs are accessed using POST and sets Content-Security-Policy headers that prevent execution of unsafe elements when the URL is accessed directly.\n\nIn case of problems with this change, these protections can be disabled by setting the [Java system properties](https://www.jenkins.io/doc/book/managing/system-properties/) `hudson.markup.MarkupFormatter.previewsAllowGET` to `true` and/or `hudson.markup.MarkupFormatter.previewsSetCSP` to `false`. Doing either is discouraged.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.263.2"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 2.263.1"
}
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.264"
}, {
"fixed" : "2.275"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 2.274"
}
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21610"
}, {
"type" : "WEB",
"url" : "https://github.com/jenkinsci/jenkins/commit/89ec0c40b68cd1e4e9f9ef5ebcafd87e7fa16589"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/jenkinsci/jenkins"
}, {
"type" : "WEB",
"url" : "https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-2153"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-79" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2022-06-24T00:51:20Z",
"nvd_published_at" : "2021-01-13T16:15:00Z"
}
}