In the Linux kernel before version 4.12, Kerberos 5 tickets decoded when using the RXRPC keys incorrectly assumes the size of a field. This could lead to the size-remaining variable wrapping and the data pointer going over the end of the buffer. This could possibly lead to memory corruption and possible privilege escalation.
https://www.debian.org/security/2017/dsa-3945
https://www.debian.org/security/2017/dsa-3927
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7482
https://access.redhat.com/errata/RHSA-2019:0641
http://www.securitytracker.com/id/1038787