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Jenkins Security Advisory Patches Critical RCE in Pipeline Plugin

Tuesday, March 3, 2026 at 09:00 AM UTC·Source: Jenkins Security Advisory

Updated: Wednesday, March 4, 2026 at 11:00 AM UTC

Executive Summary

Critical deserialization vulnerability in Jenkins Pipeline plugin allows unauthenticated RCE. 150,000+ Jenkins instances exposed.

Analysis

CVE-2026-4321 is a Java deserialization vulnerability in the Jenkins Pipeline: Groovy plugin allowing unauthenticated attackers to execute arbitrary code on Jenkins controllers. Shodan data shows over 150,000 internet-facing Jenkins instances, many running the vulnerable plugin version. Active exploitation detected within 72 hours of advisory publication.

Timeline

Discovered
Feb 25, 2026
Exploitation Detected
Mar 2, 2026
Published
Mar 3, 2026
Patch Available
Mar 3, 2026

Indicators of Compromise (1)

CVE (1)
CVE-2026-4321
NVDMITRE CVE
Source Attribution

Originally published by Jenkins Security Advisory on Mar 3, 2026. Verified by: Jenkins Project, CISA.

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