CISA-confirmed known exploited vulnerability

CVE-2023-33010

Zyxel Multiple Firewalls Buffer Overflow Vulnerability

Zyxel · Multiple Firewalls

Vulnerability details

Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the ID processing function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.

Added to CISA KEV: 2023-06-05

Ransomware campaign use: Unknown

CISA due date: 2023-06-26

Defensive guidance from CISA

Apply updates per vendor instructions.

This is the source's required-action field, not an independently validated patch procedure. Refer to the vendor for exact affected versions and fixes.

Source catalog date: 2026-11-06T19:44:45.1797Z · Last retrieved: 2026-11-06 21:02:26 UTC

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