CVE-2026-42521: Jenkins Matrix Authorization Strategy Plugin 2.0-beta-1 through 3.2.9 (both inclusive) invokes parameterless c

Routine

MEDIUM 6.5UPGRADE

CVE-2026-42521 is a medium-severity flaw (CVSS 6.5) affecting matrix authorization strategy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 classpa

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-04-29
Last modified	2026-10-26

Publisher (CNA): Jenkins Project · Vendor: jenkins

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-29 14:16 UTCPublished CVE record published
2026-10-26 20:10 UTCUpdated Record last modified

jenkins matrix authorization strategy UPGRADE

Affected: >= 2.1 and < 3.2.10 · 2.0 beta1 · 2.0 beta2 · 2.0 beta3

Fixed in: 3.2.10

Safe to downgrade to: a release before 2.0

1. Check installed version

apt-cache policy matrix-authorization-strategy || rpm -q matrix-authorization-strategy || matrix-authorization-strategy --version

2. UPGRADE to 3.2.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade matrix-authorization-strategy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade matrix-authorization-strategy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison matrix-authorization-strategy sudo apt install matrix-authorization-strategy=<VERSION_BEFORE_2.0> sudo apt-mark hold matrix-authorization-strategy

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list matrix-authorization-strategy sudo dnf downgrade matrix-authorization-strategy-<VERSION_BEFORE_2.0> sudo dnf versionlock add matrix-authorization-strategy

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42521?

matrix authorization strategy: upgrade to 3.2.10. Exact commands for each OS are on this page.

Is CVE-2026-42521 being exploited?

CVE-2026-42521 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42521 affect?

CVE-2026-42521 affects matrix authorization strategy. Severity is medium (CVSS 6.5). 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

How urgent is CVE-2026-42521?

Priority 27/100. No elevated risk signals yet.

Software pages

Jenkins vulnerabilities

References

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