CVEvulnerability

CVE-2023-33009

9.8 CRITICAL Known exploited Published 2023-05-24 Modified 2026-06-17 Official page ↗

CISA Known Exploited Vulnerability

Zyxel Multiple Firewalls Buffer Overflow Vulnerability — Zyxel Multiple Firewalls

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.

Added to KEV
2023-06-05
Remediation due
2023-06-26
Ransomware use
Unknown
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
Status
Analyzed
Published
2023-05-24
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1 ([email protected])
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-120

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.

Affected configurations

• zyxel atp100 firmware (>= 4.60 < 5.36) • zyxel atp100 firmware 5.36 • zyxel atp200 firmware (>= 4.60 < 5.36) • zyxel atp200 firmware 5.36 • zyxel atp500 firmware (>= 4.60 < 5.36) • zyxel atp500 firmware 5.36 • zyxel atp100w firmware (>= 4.60 < 5.36) • zyxel atp100w firmware 5.36 • zyxel atp700 firmware (>= 4.60 < 5.36) • zyxel atp700 firmware 5.36 • zyxel atp800 firmware (>= 4.60 < 5.36) • zyxel atp800 firmware 5.36 • zyxel usg flex 100 firmware (>= 4.60 < 5.36) • zyxel usg flex 100 firmware 5.36 • zyxel usg flex 50 firmware (>= 4.60 < 5.36) • zyxel usg flex 50 firmware 5.36 • zyxel usg flex 200 firmware (>= 4.60 < 5.36) • zyxel usg flex 200 firmware 5.36 • zyxel usg flex 500 firmware (>= 4.60 < 5.36) • zyxel usg flex 500 firmware 5.36 • zyxel usg flex 700 firmware (>= 4.60 < 5.36) • zyxel usg flex 700 firmware 5.36 • zyxel usg flex 100w firmware (>= 4.60 < 5.36) • zyxel usg flex 100w firmware 5.36 • zyxel usg flex 50w firmware (>= 4.60 < 5.36) • zyxel usg flex 50w firmware 5.36 • zyxel usg 20w-vpn firmware (>= 4.60 < 5.36) • zyxel usg 20w-vpn firmware 5.36 • zyxel vpn100 firmware (>= 4.60 < 5.36) • zyxel vpn100 firmware 5.36 • zyxel vpn50 firmware (>= 4.60 < 5.36) • zyxel vpn50 firmware 5.36 • zyxel vpn300 firmware (>= 4.60 < 5.36) • zyxel vpn300 firmware 5.36 • zyxel vpn1000 firmware (>= 4.60 < 5.36) • zyxel vpn1000 firmware 5.36 • zyxel usg20-vpn firmware (>= 4.60 < 5.36) • zyxel usg20-vpn firmware 5.36 • zyxel usg 40 firmware (>= 4.60 < 4.73) • zyxel usg 40 firmware 4.73 • zyxel usg 40w firmware (>= 4.60 < 4.73) • zyxel usg 40w firmware 4.73 • zyxel usg 60w firmware (>= 4.60 < 4.73) • zyxel usg 60w firmware 4.73 • zyxel usg 60 firmware (>= 4.60 < 4.73) • zyxel usg 60 firmware 4.73

Related

Weakness · CWE (1)

  • CWE-120 Buffer Copy without Checking Size of Input weakness

References