# CVE-2026-42521: matrix-auth — Fixed in 3.2.10

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

# CVE-2026-42521 — matrix-auth

MEDIUM 

CVE-2026-42521 is a medium-severity (CVSS 6.5) Deserialization of Untrusted Data vulnerability in org.jenkins-ci.plugins:matrix-auth. A fix is available for org.jenkins-ci.plugins:matrix-auth — see the affected versions and patch details below.

Jenkins Matrix Authorization Strategy Plugin: Unsafe deserialization allows invocation of parameterless constructors

Also known as[GHSA-jp9r-mmhw-vff3](/vulnerability/GHSA-jp9r-mmhw-vff3)

Published

Apr 29, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### No confirmed exploitation observed yet

-   CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42521.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk

0.00%0.29%0.59%0.89%0.0%0.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

1 pkg affected

☕`org.jenkins-ci.plugins:matrix-auth`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

## Description

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.

This can be abused by 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.

Matrix Authorization Strategy Plugin 3.2.10 verifies that the class being instantiated is an inheritance strategy implementation, preventing instantiation of arbitrary types.

## Affected Packages

1 total 1 fixed

Ecosystem

Package

Vulnerable range

Fix

☕Maven

`org.jenkins-ci.plugins:matrix-auth` 

≥ 2.0-beta-1&&< 3.2.10

3.2.10`org.jenkins-ci.plugins:matrix-auth:3.2.10`

## Affected Products

1 product · 4 configurations

Application

`matrix authorization strategy`jenkins

≥ 2.1 && < 3.2.10

1 version

2.0

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:matrix-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update org.jenkins-ci.plugins:matrix-auth to 3.2.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42521 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
    

## Frequently Asked Questions

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. This can be abused by 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. Matrix Authorization Strategy Plugin 3.2.10 verifies that the class being instantiated is an inheritance strategy implementation, p

O3 Security · Impact-Aware SCA

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