kernel/ptrace.c in the Linux kernel through 4.4.1 mishandles uid and gid mappings, which allows local users to gain privileges by establishing a user namespace, waiting for a root process to enter that namespace with an unsafe uid or gid, and then using the ptrace system call. NOTE: the vendor states "there is no kernel bug here.
- http://www.openwall.com/lists/oss-security/2015/12/17/12
- https://github.com/ARPSyndicate/cve-scores