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PatchSiren cyber security CVE debrief

CVE-2026-53437 Jenkins Project CVE debrief

CVE-2026-53437 is a medium-severity vulnerability in Jenkins that allows attackers to perform phishing attacks. The vulnerability is caused by improper validation of redirect URLs after login, which can be exploited by attackers to redirect users to malicious sites. The vulnerability affects Jenkins versions 2.567 and earlier, as well as LTS versions 2.555.2 and earlier.

Vendor
Jenkins Project
Product
Jenkins
CVSS
MEDIUM 4.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-08-27
Advisory published
2026-06-10
Advisory updated
2026-08-27

Who should care

Administrators and users of Jenkins versions 2.567 and earlier, LTS versions 2.555.2 and earlier, should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability is caused by Jenkins improperly determining that a redirect URL after login is legitimately pointing to Jenkins when it contains tab or newline characters between `//`. This allows attackers to perform phishing attacks by redirecting users to malicious sites.

Defensive priority

MEDIUM

Recommended defensive actions

  • Upgrade to Jenkins version 2.568 or later, or LTS version 2.555.3 or later.
  • Refer to the vendor advisory for more information: [ref-4](https://www.jenkins.io/security/advisory/2026-06-10/#SECURITY-3711+3755)

Evidence notes

CVE-2026-53437 has a CVSS score of 4.3 and is classified as MEDIUM severity. The vulnerability is related to CWE-601.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53437 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53437

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53437 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53437

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.