Researchers discovered that the original patch for the Dirty COW vulnerability (CVE-2016-5195) is affected by a security flaw. The vulnerability was rated as Important and it received a score 6.1 on the CVSS scale, it was patched in October 2016. The name Dirty COW is due to a race condition in the way the Linux kernels memory subsystem handles copy-on-write (COW) breakage of private read-only memory mappings.”]
Source: https://securityaffairs.co/wordpress/66244/hacking/dirty-cow-patch-flaw.html