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PatchSiren cyber security CVE debrief

CVE-2026-53440 Jenkins Project CVE debrief

CVE-2026-53440 is a medium-severity vulnerability in Jenkins 2.567 and earlier, LTS 2.555.2 and earlier. The vulnerability occurs because the 'from' parameter in the 'Delegate to servlet container' security realm is not properly validated, allowing attackers to redirect users to an attacker-controlled domain after login, which can be used for phishing attacks.

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
2026-06-12
Advisory published
2026-06-10
Advisory updated
2026-06-12

Who should care

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

Technical summary

The vulnerability has a CVSS score of 4.3 and is classified as CWE-601. The affected versions of Jenkins are 2.567 and earlier, and LTS 2.555.2 and earlier. The vulnerability can be mitigated by updating to a fixed version of Jenkins.

Defensive priority

medium

Recommended defensive actions

  • Update Jenkins to version 2.568 or later, or LTS 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-3721)

Evidence notes

The information provided is based on the CVE record and the NVD detail page.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53440 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53440

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

  • CVE-2026-53440 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53440

    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.