CVE-2011-0997: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 84.6% chance of exploitation in the next 30 days.

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-ESV-R2 allows remote attackers to execute arbitrary commands via shell metacharacters in a hostname obtained from a DHCP message, as demonstrated by a hostname that is provided to dhclient-script.

Affected products

• Canonical Ubuntu Linux: version 6.06 only; version 8.04 only; version 9.10 only; version 10.04 only; version 10.10 only
• Debian Debian Linux: version 5.0 only; version 6.0 only; version 7.0 only
• ISC Dhcp: version 3.0 only; version 3.0.1 only; version 3.0.2 only; version 3.0.3 only; version 3.0.4 only; version 3.0.5 only; …

Published 2011-04-08. Last modified 2026-06-16.