CVE Watch—

CVE-2023-33009

Zyxel Multiple Firewalls Buffer Overflow Vulnerability

CVSS

—

No CVSS

EPSS

28.1%

p98

KEV

YES

Jun 5, 2023

Exploit Today

0-100

Published: — · Last modified: —

EPSS · 30d

28.1%EPSS · 30 days28.1%

2026-06-302026-07-16

KEV catalog record

Product

Zyxel / Multiple Firewalls

Vulnerability

Zyxel Multiple Firewalls Buffer Overflow Vulnerability

Added to KEV

Jun 5, 2023

Remediate by

Jun 26, 2023

Known ransomware use

Summary description

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

Required action

Apply updates per vendor instructions.

Notes

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewalls; https://nvd.nist.gov/vuln/detail/CVE-2023-33009

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