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.