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

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). Vendors: Jenkins, 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
    # 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

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