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CVE-2026-84646 Jenkins Project CVE debrief

CVE-2026-84646 is a vulnerability in Jenkins that allows attackers with Overall/Read permission to create user objects by submitting crafted XML. The CVE record was published on 2026-09-02T16:17:29.313Z and has been modified since then. The NVD entry is currently Analyzed. This vulnerability affects Jenkins versions 2.579 and earlier, as well as LTS versions 2.568.2 and earlier. The vulnerability allows user objects to appear as nested field values in other deserialized XML objects, enabling attackers to create user objects. Defenders should verify exposure, restrict XML deserialization, and monitor for suspicious activity.

Vendor
Jenkins Project
Product
Jenkins
CVSS
MEDIUM 4.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-02
Original CVE updated
2026-09-11
Advisory published
2026-09-02
Advisory updated
2026-09-11

Who should care

Jenkins administrators and users with Overall/Read permission should assess exposure and verify instance security. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Additionally, they should plan vendor-supported updates or mitigations through normal change control where exposure is confirmed and review compensating controls for exposed systems.

Why it matters

CVE-2026-84646 allows attackers with Overall/Read permission to create user objects in Jenkins via crafted XML. Defenders should verify exposure, restrict XML deserialization, and monitor for suspicious activity.

  • Potential unauthorized user object creation
  • Required verification of Jenkins instance exposure
  • Necessary restriction of XML deserialization to trusted sources

Technical summary

In Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, user objects can appear as nested field values in other deserialized XML objects, allowing attackers with Overall/Read permission to create user objects by submitting crafted XML. This vulnerability is related to XML deserialization and can be exploited by attackers with Overall/Read permission. The vulnerability affects Jenkins instances that process user-submitted XML data.

Defensive priority

Defenders should prioritize verifying exposure in Jenkins instances, especially those with user-submitted XML data.

Recommended defensive actions

  • Verify Jenkins instance exposure, especially with user-submitted XML data
  • Restrict XML deserialization to trusted sources
  • Monitor for suspicious user object creation

Evidence notes

The vulnerability exists in Jenkins 2.579 and earlier, LTS 2.568.2 and earlier. User objects can appear as nested field values in other deserialized XML objects.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-84646 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-84646

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

  • CVE-2026-84646 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-84646

    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.