In FreeBSD 12.1-STABLE before r359565, 12.1-RELEASE before p7, 11.4-STABLE before r362975, 11.4-RELEASE before p1, and 11.3-RELEASE before p11, missing synchronization in the IPV6_2292PKTOPTIONS socket option set handler contained a race condition allowing a malicious application to modify memory after being freed, possibly resulting in code execution.
https://security.netapp.com/advisory/ntap-20200724-0002/
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:20.ipv6.asc