CVE-2021-32827: Mockserver Injection Vulnerability

MODERATE
Advisory Identifier: GHSA-v3cg-h3f6-2242
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CVSS 6.1
CWE-79 CWE-74
Published
Advisory Summary

CVE-2021-32827 is a MODERATE (CVSS 6.1) injection vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mockserver libraries in the Maven ecosystem. The issue involves injection in mockserver. Remediation is available in the latest vendor maintenance releases.

CVE-2021-32827 at a Glance

CVE Identifier CVE-2021-32827
GHSA Identifier GHSA-v3cg-h3f6-2242
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 Mockserver
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:H/PR:N/UI:R/S:C/C:N/I:H/A:N).

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

How to Fix CVE-2021-32827

To remediate this vulnerability, upgrade all affected Mockserver 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.mock-server:mockserver fixed: Latest secure release 
<dependency>
    <groupId>org.mock-server</groupId>
    <artifactId>mockserver</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.mock-server

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-32827, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.mock-server

Analyze the terminal output to locate any version of Mockserver 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.mock-server 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 Mockserver, 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

MockServer is open source software which enables easy mocking of any system you integrate with via HTTP or HTTPS. An attacker that can trick a victim into visiting a malicious site while running MockServer locally, will be able to run arbitrary code on the MockServer machine. With an overly broad default CORS configuration MockServer allows any site to send cross-site requests. Additionally, MockServer allows you to create dynamic expectations using Javascript or Velocity templates. Both engines may allow an attacker to execute arbitrary code on-behalf of MockServer. By combining these two issues (Overly broad CORS configuration + Script injection), an attacker could serve a malicious page so that if a developer running MockServer visits it, they will get compromised. For more details including a PoC see the referenced GHSL-2021-059.

CVE-2021-32827 Affected Mockserver Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
org.mock-server:mockserver
maven/org.mock-server/mockserver
Maven
≤ 5.11.2

References

NVD — CVE-2021-32827 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-32827
Mockserver Source Repository REPOSITORY
https://github.com/mock-server/mockserver
GitHub Advisory / Wiki ADVISORY
https://securitylab.github.com/advisories/GHSL-2021-059-mockserver
Mockserver Security Information SECURITY
https://www.oracle.com/security-alerts/cpujan2022.html

Frequently Asked Questions

What is CVE-2021-32827?
CVE-2021-32827 is a security vulnerability in Mockserver involving Injection in MockServer under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Mockserver versions are affected?
Affected versions include releases prior to current release patches across affected packages: org.mock-server:mockserver.
What version fixes CVE-2021-32827?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is mockserver affected?
Yes, org.mock-server:mockserver 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-2021-32827?
CVE-2021-32827 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N.
What CWE is associated with CVE-2021-32827?
CVE-2021-32827 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-2021-32827?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.mock-server'. 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-v3cg-h3f6-2242",
  "modified" : "2022-02-08T21:01:17Z",
  "published" : "2021-08-30T16:24:38Z",
  "aliases" : [ "CVE-2021-32827" ],
  "summary" : "Injection in MockServer",
  "details" : "MockServer is open source software which enables easy mocking of any system you integrate with via HTTP or HTTPS. An attacker that can trick a victim into visiting a malicious site while running MockServer locally, will be able to run arbitrary code on the MockServer machine. With an overly broad default CORS configuration MockServer allows any site to send cross-site requests. Additionally, MockServer allows you to create dynamic expectations using Javascript or Velocity templates. Both engines may allow an attacker to execute arbitrary code on-behalf of MockServer. By combining these two issues (Overly broad CORS configuration + Script injection), an attacker could serve a malicious page so that if a developer running MockServer visits it, they will get compromised. For more details including a PoC see the referenced GHSL-2021-059.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.mock-server:mockserver"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "5.11.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-32827"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mock-server/mockserver"
  }, {
    "type" : "ADVISORY",
    "url" : "https://securitylab.github.com/advisories/GHSL-2021-059-mockserver"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpujan2022.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74", "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-26T19:35:37Z",
    "nvd_published_at" : "2021-08-16T21:15:00Z"
  }
}