K12903841 : Linux kernel vulnerabilities CVE-2015-4170, CVE-2015-6526, and CVE-2015-7837

Security Advisory Description

• CVE-2015-4170

Race condition in the ldsem_cmpxchg function in drivers/tty/tty_ldsem.c in the Linux kernel before 3.13-rc4-next-20131218 allows local users to cause a denial of service (ldsem_down_read and ldsem_down_write deadlock) by establishing a new tty thread during shutdown of a previous tty thread.

• CVE-2015-6526

The perf_callchain_user_64 function in arch/powerpc/perf/callchain.c in the Linux kernel before 4.0.2 on ppc64 platforms allows local users to cause a denial of service (infinite loop) via a deep 64-bit userspace backtrace.

• CVE-2015-7837

The Linux kernel, as used in Red Hat Enterprise Linux 7, kernel-rt, and Enterprise MRG 2 and when booted with UEFI Secure Boot enabled, allows local users to bypass intended securelevel/secureboot restrictions by leveraging improper handling of secure_boot flag across kexec reboot.

Impact

None. F5 products are not affected by this vulnerability.