CVE-2017-18344: Canonical Ubuntu Linux

Medium severity, CVSS 5.5. EPSS: 3.4% chance of exploitation in the next 30 days.

The timer_create syscall implementation in kernel/time/posix-timers.c in the Linux kernel before 4.14.8 doesn't properly validate the sigevent->sigev_notify field, which leads to out-of-bounds access in the show_timer function (called when /proc/$PID/timers is read). This allows userspace applications to read arbitrary kernel memory (on a kernel built with CONFIG_POSIX_TIMERS and CONFIG_CHECKPOINT_RESTORE).

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 14.04 only
• Linux Linux Kernel: before 4.14.8 (fixed in 4.14.8)
• Red Hat Enterprise Linux Desktop: version 7.0 only
• Red Hat Enterprise Linux Server: version 7.0 only
• Red Hat Enterprise Linux Server Aus: version 7.2 only; version 7.3 only; version 7.4 only
• Red Hat Enterprise Linux Server Eus: version 7.3 only; version 7.5 only
• Red Hat Enterprise Linux Server Tus: version 7.2 only; version 7.3 only; version 7.4 only
• Red Hat Enterprise Linux Workstation: version 7.0 only
• Red Hat Mrg Realtime: version 2.0 only

Published 2018-07-26. Last modified 2026-06-17.