The vulnerability was discovered by security researcher Phil Oester and is called "DIRTY COW".
It is believed that the vulnerability was being exploited in the wild for quite some time.
Vulnerable component: Linux kernel
CVSSv3 score: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The vulnerability allows a local user to obtain elevated privileges on the target system.
The weakness is due to race condition in the kernel memory subsystem in the management of copy-on-write operations on read-only memory mappings that lets attackers to overwrite kernel memory and gain kernel-level privileges.
Successful exploitation of the vulnerability results in gaining of root privileges on the vulnerable system.
Note: the vulnerability was being actively exploited.