CVE-2011-0997: dhclient in ISC DHCP 3.0.x through 4.2.x before 4.2.1-P1, 3.1-ESV before 3.1-ESV-R1, and 4.1-ESV before 4.1...

Security readout for executives and security teams

A malicious DHCP server or network position could give a vulnerable client a crafted hostname that causes ISC dhclient scripts to run unintended commands. This matters most for legacy systems that still use affected ISC DHCP versions and connect to untrusted or shared networks. Exposure is most likely on older Linux or Unix systems, appliances, or images running vulnerable ISC dhclient versions. Risk increases where clients accept DHCP from untrusted, shared, or compromised local networks. Treat as high priority for legacy estate cleanup and network-exposed clients. Modern patched systems are unlikely to be affected, but old base images and appliances can keep this risk alive. Mitigation focus: Upgrade ISC DHCP/dhclient to the fixed versions or vendor-fixed packages.; Check Red Hat, Fedora, Mandriva, HP, or platform vendor advisories for package mapping.; Prioritize systems using DHCP on untrusted, guest, wireless, or shared networks..

Prepared

Jun 24, 2026, 13:28 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.