Jenkins RCE Flaw Exploited by Attackers in the Wild

An actively exploited remote code execution vulnerability (CVE-2026-53435) in Jenkins, due to insecure deserialization of config.xml, is being abused in the wild; attackers scan for exposed or misconfigured Jenkins instances to upload or modify config.xml, trigger unsafe deserialization, execute arbitrary code, deploy backdoors or cryptominers, and potentially tamper with build pipelines. Observed indicators include anomalous HTTP POSTs to configuration endpoints, unexpected config.xml changes, and outbound connections from Jenkins servers; recommended mitigations are to restrict public access, apply patches or vendor workarounds, enforce strong authentication, disable unnecessary plugins, and deploy WAF/IDS and continuous monitoring.