Stable Linux Kernel Updates Roll Out To Address "Dirty COW" CVE

The supported Linux 4.8/4.7/4.4 kernel series have seen stable point releases today to address a new CVE security issue nicknamed "Dirty COW" that is a local privilege escalation issue and could allow attackers to overwrite files to which they don't own write access.

CVE-2016-5195 was made public overnight as a kernel local privilege escalation issue. As described, "A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system. This could be abused by an attacker to modify existing setuid files with instructions to elevate privileges. An exploit using this technique has been found in the wild."

The fresh releases of Linux 4.8.3, 4.7.9, and 4.4.26 address this CVE. There's also a DirtyCOW.ninja site setup devoted to this bug, following recent security nicknames like Heartbleed, Shellshock, etc.

In the upstream kernel fix, Linus Torvalds describes this as an "ancient bug" dating back many years.