CVE-2021-21682: Jenkins core Improper Handling Of Equivalent Directory Vulnerability
MODERATECVE-2021-21682 is a MODERATE (CVSS 6.3) improper handling of equivalent directory vulnerability (CWE-42: Path Equivalence: 'filename.' (Trailing Dot)) affecting Jenkins core libraries in the Maven ecosystem. The issue involves improper handling of equivalent directory names on windows in jenkins. Remediation is available by upgrading affected packages to version 2.315, 2.303.2.
CVE-2021-21682 at a Glance
Security Impact
CVSS: 6.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).
How to Fix CVE-2021-21682
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>2.315</version>
</dependency><dependency>
<groupId>org.jenkins-ci.main</groupId>
<artifactId>jenkins-core</artifactId>
<version>2.303.2</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-2021-21682, 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 2.315), 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 & RFC 5280 Specification
Under RFC 5280 specifications for X.509 certificates, the Name Constraints extension defines a namespace within which all subsequent subject names in a certification path must be located. Constraints apply to various name forms including directory names, IP addresses, rfc822Name (email addresses), and uniformResourceIdentifier (URI) entries. Specifically, during certificate path validation, affected versions of Jenkins core failed to properly normalize or enforce boundary checks when domain names contained trailing dot (.) characters. Because domain names with a trailing dot signify fully qualified domain names (FQDNs), this omission allowed non-conforming certificates to be improperly validated as compliant with the defined name constraints.
Source Advisory Statement
CVE-2021-21682 Affected Jenkins core Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
≥ 2.304
< 2.315
|
2.315
|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
< 2.303.2
|
2.303.2
|
References
Frequently Asked Questions
What is CVE-2021-21682?
Which Jenkins core versions are affected?
What version fixes CVE-2021-21682?
Is jenkins-core affected?
What is the CVSS score of CVE-2021-21682?
What CWE is associated with CVE-2021-21682?
How can I check Maven dependencies for CVE-2021-21682?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-6q4g-84f3-mw74",
"modified" : "2022-12-15T17:39:41Z",
"published" : "2022-05-24T19:16:59Z",
"aliases" : [ "CVE-2021-21682" ],
"summary" : "Improper handling of equivalent directory names on Windows in Jenkins",
"details" : "Jenkins stores jobs and other entities on disk using their name shown on the UI as file and folder names.\n\nOn Windows, when specifying a file or folder with a trailing dot character (`example.`), the file or folder will be treated as if that character was not present (`example`). As both are legal names for jobs and other entities in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier, this could allow users with the appropriate permissions to change or replace configurations of jobs and other entities.\n\nJenkins 2.315, LTS 2.303.2 does not allow names of jobs and other entities to end with a dot character.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.304"
}, {
"fixed" : "2.315"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 2.314"
}
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.303.2"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 2.303.1"
}
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21682"
}, {
"type" : "WEB",
"url" : "https://github.com/jenkinsci/jenkins/commit/c2c2b59071265aea07f88d5e95297c0a433921c3"
}, {
"type" : "WEB",
"url" : "https://www.jenkins.io/security/advisory/2021-10-06/#SECURITY-2424"
}, {
"type" : "WEB",
"url" : "http://www.openwall.com/lists/oss-security/2021/10/06/1"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-42" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2022-12-15T17:39:41Z",
"nvd_published_at" : "2021-10-06T23:15:00Z"
}
}