CVE-2020-2099: Jenkins core Authentication Bypass Vulnerability
HIGHCVE-2020-2099 is a HIGH (CVSS 8.6) authentication bypass vulnerability (CWE-330: Use of Insufficiently Random Values) affecting Jenkins core libraries in the Maven ecosystem. The issue involves inbound tcp agent protocol/3 authentication bypass in jenkins. Remediation is available by upgrading affected packages to version 2.204.2, 2.214.
CVE-2020-2099 at a Glance
Security Impact
CVSS: 8.6
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L).
How to Fix CVE-2020-2099
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>2.204.2</version>
</dependency><dependency>
<groupId>org.jenkins-ci.main</groupId>
<artifactId>jenkins-core</artifactId>
<version>2.214</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-2020-2099, 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 2.204.2), 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-330: Use of Insufficiently Random Values, where the product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. 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-2020-2099 Affected Jenkins core Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
< 2.204.2
|
2.204.2
|
|
org.jenkins-ci.main:jenkins-core
|
Maven |
≥ 2.205
< 2.214
|
2.214
|
References
Frequently Asked Questions
What is CVE-2020-2099?
Which Jenkins core versions are affected?
What version fixes CVE-2020-2099?
Is jenkins-core affected?
What is the CVSS score of CVE-2020-2099?
What CWE is associated with CVE-2020-2099?
How can I check Maven dependencies for CVE-2020-2099?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-qp4f-2w67-c8hw",
"modified" : "2022-12-16T22:56:05Z",
"published" : "2022-05-24T17:07:40Z",
"aliases" : [ "CVE-2020-2099" ],
"summary" : "Inbound TCP Agent Protocol/3 authentication bypass in Jenkins",
"details" : "Jenkins 2.213 and earlier, LTS 2.204.1 and earlier includes support for the Inbound TCP Agent Protocol/3 for communication between controller and agents. While [this protocol has been deprecated in 2018](https://www.jenkins.io/changelog-old/#v2.128) and was recently removed from Jenkins in 2.214, it could still easily be enabled in Jenkins LTS 2.204.1, 2.213, and older.\n\nThis protocol incorrectly reuses encryption parameters which allow an unauthenticated remote attacker to determine the connection secret. This secret can then be used to connect attacker-controlled Jenkins agents to the Jenkins controller.\n\nJenkins 2.204.2 no longer allows for the use of Inbound TCP Agent Protocol/3 by default. The system property `jenkins.slaves.JnlpSlaveAgentProtocol3.ALLOW_UNSAFE` can be set to `true` to allow enabling the Inbound TCP Agent Protocol/3 in Jenkins 2.204.2, but doing so is strongly discouraged.\n\nInbound TCP Agent Protocol/3 was removed completely from Jenkins 2.214 and will not be part of Jenkins LTS after the end of the 2.204.x line.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.204.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.jenkins-ci.main:jenkins-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.205"
}, {
"fixed" : "2.214"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-2099"
}, {
"type" : "WEB",
"url" : "https://github.com/jenkinsci/jenkins/commit/5054bc6e12e1022993d719f66e289ab1d22ae854"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHBA-2020:0402"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHBA-2020:0675"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2020:0681"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2020:0683"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/jenkinsci/jenkins"
}, {
"type" : "WEB",
"url" : "https://jenkins.io/security/advisory/2020-01-29/#SECURITY-1682"
}, {
"type" : "WEB",
"url" : "http://www.openwall.com/lists/oss-security/2020/01/29/1"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-323", "CWE-330" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2022-12-16T22:56:05Z",
"nvd_published_at" : "2020-01-29T16:15:00Z"
}
}