Vulnerabilities in pkg:maven/org.jenkins-ci.plugins/cas-plugin

PACKAGE
Advisory Identifier: GHSA-2vvr-5757-qp87
Share
Advisory Summary

CVE-2021-21673 is a MODERATE (CVSS 6.1) open redirect vulnerability vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Cas plugin libraries in the Maven ecosystem. The issue involves open redirect vulnerability in jenkins cas plugin. Remediation is available by upgrading affected packages to version 1.6.1.

3 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:maven/org.jenkins-ci.plugins/cas-plugin

3 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:maven/org.jenkins-ci.plugins/cas-plugin. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-2vvr-5757-qp87 CVE-2021-21673 MODERATE Open redirect vulnerability in Jenkins CAS Plugin
GHSA-hjh8-9gxh-cx4x CVE-2023-32997 HIGH Jenkins CAS Plugin Session Fixation vulnerability
GHSA-f8r7-7hv9-7f43 CVE-2018-1000188 MODERATE Jenkins CAS Plugin Server-Side Request Forgery vulnerability

CVE-2021-21673 at a Glance

CVE Identifier CVE-2021-21673
GHSA Identifier GHSA-2vvr-5757-qp87
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Cas plugin
Package Ecosystem Maven
Published Date
Last Updated

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).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2021-21673

To remediate this vulnerability, upgrade all affected Cas plugin dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.jenkins-ci.plugins:cas-plugin fixed: 1.6.1 
<dependency>
    <groupId>org.jenkins-ci.plugins</groupId>
    <artifactId>cas-plugin</artifactId>
    <version>1.6.1</version>
</dependency>
Verify Direct and Transitive Dependencies

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.plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-21673, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

Analyze the terminal output to locate any version of Cas plugin in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.6.1), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.plugins 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-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Cas plugin, 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

Jenkins CAS Plugin 1.6.0 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins. This allows attackers to perform phishing attacks by having users go to a Jenkins URL that will forward them to a different site after successful authentication. Jenkins CAS Plugin 1.6.1 only redirects to relative (Jenkins) URLs.

CVE-2021-21673 Affected Cas plugin Versions

1 component(s)
Fixed Versions:
1.6.1
Product / Package Ecosystem Affected Versions Fixed Version
org.jenkins-ci.plugins:cas-plugin
maven/org.jenkins-ci.plugins/cas-plugin
Maven
< 1.6.1
1.6.1

References

NVD — CVE-2021-21673 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-21673
Security Fix Commit FIX COMMIT
https://github.com/jenkinsci/cas-plugin/commit/8ac536a953156160dbabb61bdb3b9bc75c3d0ef9
Cas plugin Source Repository REPOSITORY
https://github.com/jenkinsci/cas-plugin
Cas plugin Security Information SECURITY
https://www.jenkins.io/security/advisory/2021-06-30/#SECURITY-2387
Cas plugin Security Information SECURITY
http://www.openwall.com/lists/oss-security/2021/06/30/1

Frequently Asked Questions

What is CVE-2021-21673?
CVE-2021-21673 is a security vulnerability in Cas plugin involving Open redirect vulnerability in Jenkins CAS Plugin under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Cas plugin versions are affected?
Affected versions include releases prior to 1.6.1 across affected packages: org.jenkins-ci.plugins:cas-plugin.
What version fixes CVE-2021-21673?
Upgrading to 1.6.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is cas-plugin affected?
Yes, org.jenkins-ci.plugins:cas-plugin is affected in releases prior to 1.6.1. Upgrade your dependency to 1.6.1 or later.
What is the CVSS score of CVE-2021-21673?
CVE-2021-21673 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2021-21673?
CVE-2021-21673 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check Maven dependencies for CVE-2021-21673?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jenkins-ci.plugins'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2vvr-5757-qp87",
  "modified" : "2023-10-27T15:34:11Z",
  "published" : "2022-05-24T19:06:35Z",
  "aliases" : [ "CVE-2021-21673" ],
  "summary" : "Open redirect vulnerability in Jenkins CAS Plugin",
  "details" : "Jenkins CAS Plugin 1.6.0 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins.\n\nThis allows attackers to perform phishing attacks by having users go to a Jenkins URL that will forward them to a different site after successful authentication.\n\nJenkins CAS Plugin 1.6.1 only redirects to relative (Jenkins) URLs.",
  "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.plugins:cas-plugin"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.6.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.6.0"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21673"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jenkinsci/cas-plugin/commit/8ac536a953156160dbabb61bdb3b9bc75c3d0ef9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/cas-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://www.jenkins.io/security/advisory/2021-06-30/#SECURITY-2387"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2021/06/30/1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-12-16T15:19:45Z",
    "nvd_published_at" : "2021-06-30T17:15:00Z"
  }
}