CVE-2018-12896 Information

Description

An issue was discovered in the Linux kernel through 4.17.3. An Integer Overflow in kernel/time/posix-timers.c in the POSIX timer code is caused by the way the overrun accounting works. Depending on interval and expiry time values the overrun can be larger than INT_MAX but the accounting is int based. This basically makes the accounting values which are visible to user space via timer_getoverrun(2) and siginfo::si_overrun random. For example a local user can cause a denial of service (signed integer overflow) via crafted mmap futex timer_create and timer_settime system calls.

CVSS Vector

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://bugzilla.kernel.org/show_bug.cgi?id=200189 https://github.com/lcytxw/bug_repro/tree/master/bug_200189 https://github.com/torvalds/linux/commit/78c9c4dfbf8c04883941445a195276bb4bb92c76 https://lists.debian.org/debian-lts-announce/2019/03/msg00017.html https://lists.debian.org/debian-lts-announce/2019/03/msg00034.html https://lists.debian.org/debian-lts-announce/2019/04/msg00004.html https://usn.ubuntu.com/3847-1/ https://usn.ubuntu.com/3847-2/ https://usn.ubuntu.com/3847-3/ https://usn.ubuntu.com/3848-1/ https://usn.ubuntu.com/3848-2/ https://usn.ubuntu.com/3849-1/ https://usn.ubuntu.com/3849-2/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5