isakmpd payload handling denial-of-service vulnerabilities

Numerous errors in isakmpd’s input packet validation lead to
denial-of-service vulnerabilities. From the Rapid7 advisory:

The ISAKMP packet processing functions in OpenBSD’s
isakmpd daemon contain multiple payload handling flaws
that allow a remote attacker to launch a denial of
service attack against the daemon.
Carefully crafted ISAKMP packets will cause the isakmpd
daemon to attempt out-of-bounds reads, exhaust available
memory, or loop endlessly (consuming 100% of the CPU).