CVE-2023-33009
Description
A buffer overflow vulnerability in the notification function in Zyxel ATP series firmware versions 4.60 through 5.36 Patch 1, USG FLEX series firmware versions 4.60 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.60 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.60 through 5.36 Patch 1, VPN series firmware versions 4.60 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.60 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.
Summary dbcve.org
A stack/heap buffer overflow exists in the notification function of multiple Zyxel firewall and VPN appliance firmware versions (4.60 through 5.36 Patch 1 on ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, and VPN series; 4.60 through 4.73 Patch 1 on ZyWALL/USG series). Because the flaw is reachable without authentication, an unauthenticated remote attacker can send crafted input to the notification routine to trigger the overflow, resulting in denial-of-service and potentially remote code execution on the affected device.
Mitigation
Upgrade affected Zyxel appliances to a fixed firmware version beyond 5.36 Patch 1 (or 4.73 Patch 1 for ZyWALL/USG series) as published by Zyxel; until patched, restrict management/notification service exposure to trusted networks and monitor for anomalous requests against the device's notification endpoint.