A null pointer dereference vulnerability in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1 and USG FLEX series firmware versions from 4.50 through 5.37 Patch 1 could allow a LAN-based attacker to cause denial-of-service (DoS) conditions by downloading a crafted RAR compressed file onto a LAN-side host if the firewall has the “Anti-Malware” feature enabled.