CVE-2018-6553: Canonical Ubuntu Linux

High severity, CVSS 8.8. EPSS: 0.4% chance of exploitation in the next 30 days.

The CUPS AppArmor profile incorrectly confined the dnssd backend due to use of hard links. A local attacker could possibly use this issue to escape confinement. This flaw affects versions prior to 2.2.7-1ubuntu2.1 in Ubuntu 18.04 LTS, prior to 2.2.4-7ubuntu3.1 in Ubuntu 17.10, prior to 2.1.3-4ubuntu0.5 in Ubuntu 16.04 LTS, and prior to 1.7.2-0ubuntu1.10 in Ubuntu 14.04 LTS.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only; version 18.04 only
• Cups Cups: affected versions not specified
• Debian Debian Linux: version 8.0 only; version 9.0 only

Published 2018-08-10. Last modified 2026-06-17.