How severe is CVE-2026-42523?

CVE-2026-42523 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-42523 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42523?

CVE-2026-42523 affects Jenkins Github. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42523?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-42523 have an EU (EUVD) identifier?

Yes. CVE-2026-42523 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26225.

When was CVE-2026-42523 published?

CVE-2026-42523 was published on 2026-04-29 and last updated on 2026-06-17.

CVE-2026-42523

CVE-2026-42523 is a critical-severity vulnerability in Jenkins Github with a CVSS 3.x base score of 9.0. 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-79.

Key facts

Severity: Critical (CVSS 3.x base score 9.0)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26225
Weakness: CWE-79
Affected product: Jenkins Github
Published: 2026-04-29
Last modified: 2026-06-17

Description

Jenkins GitHub Plugin 1.46.0 and earlier improperly processes the current job URL as part of JavaScript implementing validation of the feature "GitHub hook trigger for GITScm polling", resulting in a stored cross-site scripting (XSS) vulnerability exploitable by non-anonymous attackers with Overall/Read permission.

Frequently asked questions

What is CVE-2026-42523?: Jenkins GitHub Plugin 1.46.0 and earlier improperly processes the current job URL as part of JavaScript implementing validation of the feature "GitHub hook trigger for GITScm polling", resulting in a stored cross-site scripting (XSS) vulnerability exploitable by non-anonymous attackers with Overall/Read permission.
How severe is CVE-2026-42523?: CVE-2026-42523 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-42523 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42523?: CVE-2026-42523 affects Jenkins Github. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42523?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-42523 have an EU (EUVD) identifier?: Yes. CVE-2026-42523 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26225.
When was CVE-2026-42523 published?: CVE-2026-42523 was published on 2026-04-29 and last updated on 2026-06-17.

References

https://www.jenkins.io/security/advisory/2026-04-29/#SECURITY-3704

Affected products (1)

cpe:2.3:a:jenkins:github:*:*:*:*:*:jenkins:*:*

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