CVE-2018-12896

Published: 2 July 2018

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.

From the Ubuntu Security Team

It was discovered that an integer overrun vulnerability existed in the POSIX timers implementation in the Linux kernel. A local attacker could use this to cause a denial of service.

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12896
• 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://ubuntu.com/security/notices/USN-3847-1
• https://ubuntu.com/security/notices/USN-3847-2
• https://ubuntu.com/security/notices/USN-3847-3
• https://ubuntu.com/security/notices/USN-3848-1
• https://ubuntu.com/security/notices/USN-3848-2
• https://ubuntu.com/security/notices/USN-3849-1
• https://ubuntu.com/security/notices/USN-3849-2
• NVD
• Launchpad
• Debian