CVE-2020-2096: Gitlab hook Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-8696-836p-c8qp
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2020-2096 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Gitlab hook libraries in the Maven ecosystem. The issue involves reflected xss vulnerability in jenkins gitlab-hook plugin. Remediation is available in the latest vendor maintenance releases.

CVE-2020-2096 at a Glance

CVE Identifier CVE-2020-2096
GHSA Identifier GHSA-8696-836p-c8qp
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Gitlab hook
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-2020-2096

To remediate this vulnerability, upgrade all affected Gitlab hook 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.ruby-plugins:gitlab-hook fixed: Latest secure release 
<dependency>
    <groupId>org.jenkins-ci.ruby-plugins</groupId>
    <artifactId>gitlab-hook</artifactId>
    <version>Latest secure release</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.ruby-plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-2096, inspect your build dependencies using the Maven Dependency Plugin:

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

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

Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.ruby-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-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 Gitlab hook, 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 Gitlab Hook Plugin 1.4.2 and earlier does not escape project names in the `build_now` endpoint, resulting in a reflected XSS vulnerability.

CVE-2020-2096 Affected Gitlab hook Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
org.jenkins-ci.ruby-plugins:gitlab-hook
maven/org.jenkins-ci.ruby-plugins/gitlab-hook
Maven
≤ 1.4.2

References

NVD — CVE-2020-2096 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-2096
Gitlab hook Source Repository REPOSITORY
https://github.com/jenkinsci/gitlab-hook-plugin
Gitlab hook Security Information SECURITY
https://jenkins.io/security/advisory/2020-01-15/#SECURITY-1683
Gitlab hook Security Information SECURITY
http://packetstormsecurity.com/files/155967/Jenkins-Gitlab-Hook-1.4.2-Cross-Site-Scripting.html
Gitlab hook Security Information SECURITY
http://www.openwall.com/lists/oss-security/2020/01/15/1

Frequently Asked Questions

What is CVE-2020-2096?
CVE-2020-2096 is a security vulnerability in Gitlab hook involving Reflected XSS vulnerability in Jenkins gitlab-hook Plugin under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Gitlab hook versions are affected?
Affected versions include releases prior to current release patches across affected packages: org.jenkins-ci.ruby-plugins:gitlab-hook.
What version fixes CVE-2020-2096?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is gitlab-hook affected?
Yes, org.jenkins-ci.ruby-plugins:gitlab-hook is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-2096?
CVE-2020-2096 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-2020-2096?
CVE-2020-2096 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (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.).
How can I check Maven dependencies for CVE-2020-2096?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jenkins-ci.ruby-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-8696-836p-c8qp",
  "modified" : "2022-12-21T16:46:24Z",
  "published" : "2022-05-24T17:06:23Z",
  "aliases" : [ "CVE-2020-2096" ],
  "summary" : "Reflected XSS vulnerability in Jenkins gitlab-hook Plugin",
  "details" : "Jenkins Gitlab Hook Plugin 1.4.2 and earlier does not escape project names in the `build_now` endpoint, resulting in a reflected XSS vulnerability.",
  "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.ruby-plugins:gitlab-hook"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.4.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-2096"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/gitlab-hook-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://jenkins.io/security/advisory/2020-01-15/#SECURITY-1683"
  }, {
    "type" : "WEB",
    "url" : "http://packetstormsecurity.com/files/155967/Jenkins-Gitlab-Hook-1.4.2-Cross-Site-Scripting.html"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2020/01/15/1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-12-21T16:46:24Z",
    "nvd_published_at" : "2020-01-15T16:15:00Z"
  }
}