CVE-2018-14678: Canonical Ubuntu Linux

High severity, CVSS 7.8. EPSS: 0.4% chance of exploitation in the next 30 days.

An issue was discovered in the Linux kernel through 4.17.11, as used in Xen through 4.11.x. The xen_failsafe_callback entry point in arch/x86/entry/entry_64.S does not properly maintain RBX, which allows local users to cause a denial of service (uninitialized memory usage and system crash). Within Xen, 64-bit x86 PV Linux guest OS users can trigger a guest OS crash or possibly gain privileges.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• Linux Linux Kernel: from 4.14.21, before 4.14.61 (fixed in 4.14.61); from 4.15.5, before 4.17.13 (fixed in 4.17.13)
• Xen Xen: up to and including 4.11.0

Published 2018-07-28. Last modified 2026-06-17.