A NULL Pointer Dereference vulnerability in the Packet Forwarding Engine of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). On SRX Series If Unified Threat Management (UTM) Enhanced Content Filtering (CF) is enabled and specific transit traffic is processed the PFE will crash and restart. This issue affects Juniper Networks Junos OS: 21.4 versions prior to 21.4R1-S2, 21.4R2 on SRX Series; 22.1 versions prior to 22.1R1-S1, 22.1R2 on SRX Series. This issue does not affect Juniper Networks Junos OS versions prior to 21.4R1.