How severe is CVE-2026-42521?

CVE-2026-42521 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-42521 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42521?

CVE-2026-42521 primarily affects Jenkins Matrix Authorization Strategy. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-42521?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-42521 have an EU (EUVD) identifier?

Yes. CVE-2026-42521 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26222.

When was CVE-2026-42521 published?

CVE-2026-42521 was published on 2026-04-29 and last updated on 2026-06-17.

CVE-2026-42521

CVE-2026-42521 is a medium-severity vulnerability in Jenkins Matrix Authorization Strategy with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26222
Weakness: CWE-502
Affected product: Jenkins Matrix Authorization Strategy
Published: 2026-04-29
Last modified: 2026-06-17

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, 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.

Frequently asked questions

What is CVE-2026-42521?: 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.
How severe is CVE-2026-42521?: CVE-2026-42521 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-42521 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42521?: CVE-2026-42521 primarily affects Jenkins Matrix Authorization Strategy. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42521?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42521 have an EU (EUVD) identifier?: Yes. CVE-2026-42521 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26222.
When was CVE-2026-42521 published?: CVE-2026-42521 was published on 2026-04-29 and last updated on 2026-06-17.

References

https://www.jenkins.io/security/advisory/2026-04-29/#SECURITY-3676

Affected products (4)

cpe:2.3:a:jenkins:matrix_authorization_strategy:*:*:*:*:*:jenkins:*:*
cpe:2.3:a:jenkins:matrix_authorization_strategy:2.0:beta1:*:*:*:jenkins:*:*
cpe:2.3:a:jenkins:matrix_authorization_strategy:2.0:beta2:*:*:*:jenkins:*:*
cpe:2.3:a:jenkins:matrix_authorization_strategy:2.0:beta3:*:*:*:jenkins:*:*

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