OpenAFS 1.x before 1.6.22 does not properly validate Rx ack packets, which allows remote attackers to cause a denial of service (system crash or application crash) via crafted fields, as demonstrated by an integer underflow and assertion failure for a small MTU value.
https://www.openafs.org/pages/security/OPENAFS-SA-2017-001.txt
https://www.debian.org/security/2017/dsa-4067
https://lists.debian.org/debian-lts-announce/2017/12/msg00016.html