# CVE-2026-42521: Jenkins Matrix Authorization Strategy Plugin: Unsafe deserialization allows invocation of parameterless constructors

Source: https://junglewise.ai/threats/cve-2026-42521-jenkins-matrix-authorization-strategy-plugin-unsafe  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-29  
License: CC BY 4.0 with a link back

CVE-2026-42521 · Severity: medium · CVSS 6.5 · Published 2026-04-29

Jenkins Matrix Authorization Strategy Plugin 2.0-beta-1 through 3.2.9 (both inclusive) invokes parameterless constructors of classes specified in configuration when deserializing inheritance strategies, without restricting the classes that can be instantiated, allowing attackers with Item/Configure permission to instantiate arbitrary types, which may lead to information disclosure or other impacts depending on the classes available on the classpath.

Technologies: [org.jenkins-ci.plugins:matrix-auth (Maven)](https://junglewise.ai/threats/technologies/org-jenkins-ci-plugins-matrix-auth). Vendors: [Jenkins](https://junglewise.ai/threats/vendors/jenkins), [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-42521 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42521 being exploited in the wild.

**How severe is CVE-2026-42521?** Medium severity, with a CVSS score of 6.5, published 29 April 2026.

**Which products and versions are affected?** org.jenkins-ci.plugins:matrix-auth (Maven) ECOSYSTEM:introduced=2.0-beta-1,fixed=3.2.10.

**Is there a fix for CVE-2026-42521?** Yes. org.jenkins-ci.plugins:matrix-auth (Maven): upgrade to 3.2.10 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-42521?** Check whether you run Jenkins Matrix Authorization Strategy or org.jenkins-ci.plugins:matrix-auth (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.jenkins-ci.plugins:matrix-auth (Maven): upgrade to 3.2.10 or later

  ```sh
  # set org.jenkins-ci.plugins:matrix-auth to 3.2.10 in your pom.xml or build.gradle
  ```


## Affected products

- Jenkins Matrix Authorization Strategy
- org.jenkins-ci.plugins:matrix-auth (Maven) ECOSYSTEM:introduced=2.0-beta-1,fixed=3.2.10

## Identifiers

- CVE-2026-42521
- GHSA-jp9r-mmhw-vff3

## Related threats

- [Incorrect permission checks in Jenkins Matrix Authorization Strategy Plugin may allow accessing some items](https://junglewise.ai/threats/cve-2021-21623-incorrect-permission-checks-in-jenkins-matrix-authorization)
- [Stored XSS vulnerability in Jenkins Matrix Authorization Strategy Plugin](https://junglewise.ai/threats/cve-2020-2226-stored-xss-vulnerability-in-jenkins-matrix-authorization-strategy)