What’s Vulnerable › Vulnerabilities
CVE-2017-18344
- Severity: medium (CVSS 5.5 v3.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 3.4% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2018-07-26 · updated 2026-06-17
- Weakness: CWE-125
Description
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: 12.04, 14.04
- Linux kernel: before 4.14.8 — fixed in 4.14.8
- RedHat Enterprise Linux Desktop: 7.0
- RedHat Enterprise Linux Server: 7.0
- RedHat Enterprise Linux Server Aus: 7.2, 7.3, 7.4
- RedHat Enterprise Linux Server Eus: 7.3, 7.5
- RedHat Enterprise Linux Server Tus: 7.2, 7.3, 7.4
- RedHat Enterprise Linux Workstation: 7.0
- RedHat Mrg Realtime: 2.0
How to fix
Upgrade to a fixed version: Linux kernel 4.14.8. Check the vendor advisory for mitigations.
References
- http://www.securityfocus.com/bid/104909
- http://www.securitytracker.com/id/1041414
- https://access.redhat.com/errata/RHSA-2018:2948
- https://access.redhat.com/errata/RHSA-2018:3083
- https://access.redhat.com/errata/RHSA-2018:3096
- https://access.redhat.com/errata/RHSA-2018:3459
- https://access.redhat.com/errata/RHSA-2018:3540
- https://access.redhat.com/errata/RHSA-2018:3586
- https://access.redhat.com/errata/RHSA-2018:3590
- https://access.redhat.com/errata/RHSA-2018:3591
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.8
- https://github.com/torvalds/linux/commit/cef31d9af908243421258f1df35a4a644604efbe
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