Exploited
critical
9.8
CWE
119 120
Advisory Published
Updated

CVE-2023-33009: Zyxel Multiple Firewalls Buffer Overflow Vulnerability

First published: Wed May 24 2023(Updated: )

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.

Credit: security@zyxel.com.tw security@zyxel.com.tw

Affected SoftwareAffected VersionHow to fix
Zyxel Multiple Network-Attached Storage (NAS) Devices>=4.32<5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36-patch1
Zyxel Multiple Network-Attached Storage (NAS) Devices
Zyxel Atp200 Firmware>=4.32<5.36
Zyxel Atp200 Firmware=5.36
Zyxel Atp200 Firmware=5.36-patch1
Zyxel ATP200
Zyxel Atp500 Firmware>=4.32<5.36
Zyxel Atp500 Firmware=5.36
Zyxel Atp500 Firmware=5.36-patch1
Zyxel Atp500
Zyxel Atp100w Firmware>=4.32<5.36
Zyxel Atp100w Firmware=5.36
Zyxel Atp100w Firmware=5.36-patch1
Zyxel Atp100w
Zyxel Atp700 Firmware>=4.32<5.36
Zyxel Atp700 Firmware=5.36
Zyxel Atp700 Firmware=5.36-patch1
Zyxel Atp700
Zyxel Atp800 Firmware>=4.32<5.36
Zyxel Atp800 Firmware=5.36
Zyxel Atp800 Firmware=5.36-patch1
Zyxel Atp800
Zyxel Usg Flex 100 Firmware>=4.50<5.36
Zyxel Usg Flex 100 Firmware=5.36
Zyxel Usg Flex 100 Firmware=5.36-patch1
Zyxel Usg Flex 100
Zyxel Usg Flex 50 Firmware=5.36
Zyxel Usg Flex 50 Firmware=5.36-patch1
Zyxel Usg Flex 50
Zyxel Usg Flex 200 Firmware>=4.50<5.36
Zyxel Usg Flex 200 Firmware=5.36
Zyxel Usg Flex 200 Firmware=5.36-patch1
Zyxel Usg Flex 200
Zyxel Usg Flex 500 Firmware>=4.50<5.36
Zyxel Usg Flex 500 Firmware=5.36
Zyxel Usg Flex 500 Firmware=5.36-patch1
Zyxel Usg Flex 500
Zyxel Usg Flex 700 Firmware>=4.50<5.36
Zyxel Usg Flex 700 Firmware=5.36
Zyxel Usg Flex 700 Firmware=5.36-patch1
Zyxel Usg Flex 700
Zyxel Usg Flex 100w Firmware=5.36
Zyxel Usg Flex 100w Firmware=5.36-patch1
Zyxel Usg Flex 100w
Zyxel Usg Flex 50w Firmware>=4.25<5.36
Zyxel Usg Flex 50w Firmware=5.36
Zyxel Usg Flex 50w Firmware=5.36-patch1
Zyxel Usg Flex 50w
Zyxel Usg 20w-vpn Firmware=5.36
Zyxel Usg 20w-vpn Firmware=5.36-patch1
Zyxel Usg 20w-vpn
Zyxel Vpn100 Firmware>=4.30<5.36
Zyxel Vpn100 Firmware=5.36
Zyxel Vpn100 Firmware=5.36-patch1
Zyxel Vpn100
Zyxel Vpn50 Firmware>=4.30<5.36
Zyxel Vpn50 Firmware=5.36
Zyxel Vpn50 Firmware=5.36-patch1
Zyxel Vpn50
Zyxel Vpn300 Firmware>=4.30<5.36
Zyxel Vpn300 Firmware=5.36
Zyxel Vpn300 Firmware=5.36-patch1
Zyxel Vpn300
Zyxel Multiple Network-Attached Storage (NAS) Devices>=4.30<5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36-patch1
Zyxel Multiple Network-Attached Storage (NAS) Devices
Zyxel Usg20-vpn Firmware>=4.30<5.36
Zyxel Usg20-vpn Firmware=5.36
Zyxel Usg20-vpn Firmware=5.36-patch1
Zyxel Usg20-vpn
Zyxel Usg 40 Firmware>=4.25<4.73
Zyxel Usg 40 Firmware=4.73
Zyxel Usg 40 Firmware=4.73-patch1
Zyxel Usg 40
Zyxel Usg 40w Firmware>=4.25<4.73
Zyxel Usg 40w Firmware=4.73
Zyxel Usg 40w Firmware=4.73-patch1
Zyxel Usg 40w
Zyxel Usg 60w Firmware>=4.25<4.73
Zyxel Usg 60w Firmware=4.73
Zyxel Usg 60w Firmware=4.73-patch1
Zyxel Usg 60w
Zyxel Usg 60 Firmware>=4.25<4.73
Zyxel Usg 60 Firmware=4.73
Zyxel Usg 60 Firmware=4.73-patch1
Zyxel Usg 60
All of
Any of
Zyxel Multiple Network-Attached Storage (NAS) Devices>=4.60<5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36-patch1
Zyxel Multiple Network-Attached Storage (NAS) Devices
All of
Any of
Zyxel Atp200 Firmware>=4.60<5.36
Zyxel Atp200 Firmware=5.36
Zyxel Atp200 Firmware=5.36-patch1
Zyxel ATP200
All of
Any of
Zyxel Atp500 Firmware>=4.60<5.36
Zyxel Atp500 Firmware=5.36
Zyxel Atp500 Firmware=5.36-patch1
Zyxel Atp500
All of
Any of
Zyxel Atp100w Firmware>=4.60<5.36
Zyxel Atp100w Firmware=5.36
Zyxel Atp100w Firmware=5.36-patch1
Zyxel Atp100w
All of
Any of
Zyxel Atp700 Firmware>=4.60<5.36
Zyxel Atp700 Firmware=5.36
Zyxel Atp700 Firmware=5.36-patch1
Zyxel Atp700
All of
Any of
Zyxel Atp800 Firmware>=4.60<5.36
Zyxel Atp800 Firmware=5.36
Zyxel Atp800 Firmware=5.36-patch1
Zyxel Atp800
All of
Any of
Zyxel Usg Flex 100 Firmware>=4.60<5.36
Zyxel Usg Flex 100 Firmware=5.36
Zyxel Usg Flex 100 Firmware=5.36-patch1
Zyxel Usg Flex 100
All of
Any of
Zyxel Usg Flex 50 Firmware>=4.60<5.36
Zyxel Usg Flex 50 Firmware=5.36
Zyxel Usg Flex 50 Firmware=5.36-patch1
Zyxel Usg Flex 50
All of
Any of
Zyxel Usg Flex 200 Firmware>=4.60<5.36
Zyxel Usg Flex 200 Firmware=5.36
Zyxel Usg Flex 200 Firmware=5.36-patch1
Zyxel Usg Flex 200
All of
Any of
Zyxel Usg Flex 500 Firmware>=4.60<5.36
Zyxel Usg Flex 500 Firmware=5.36
Zyxel Usg Flex 500 Firmware=5.36-patch1
Zyxel Usg Flex 500
All of
Any of
Zyxel Usg Flex 700 Firmware>=4.60<5.36
Zyxel Usg Flex 700 Firmware=5.36
Zyxel Usg Flex 700 Firmware=5.36-patch1
Zyxel Usg Flex 700
All of
Any of
Zyxel Usg Flex 100 Firmware>=4.60<5.36
Zyxel Usg Flex 100w Firmware=5.36
Zyxel Usg Flex 100w Firmware=5.36-patch1
Zyxel Usg Flex 100w
All of
Any of
Zyxel Usg Flex 50w Firmware>=4.60<5.36
Zyxel Usg Flex 50w Firmware=5.36
Zyxel Usg Flex 50w Firmware=5.36-patch1
Zyxel Usg Flex 50w
All of
Any of
Zyxel Usg 20w-vpn Firmware>=4.60<5.36
Zyxel Usg 20w-vpn Firmware=5.36
Zyxel Usg 20w-vpn Firmware=5.36-patch1
Zyxel Usg 20w-vpn
All of
Any of
Zyxel Vpn100 Firmware>=4.60<5.36
Zyxel Vpn100 Firmware=5.36
Zyxel Vpn100 Firmware=5.36-patch1
Zyxel Vpn100
All of
Any of
Zyxel Vpn50 Firmware>=4.60<5.36
Zyxel Vpn50 Firmware=5.36
Zyxel Vpn50 Firmware=5.36-patch1
Zyxel Vpn50
All of
Any of
Zyxel Vpn300 Firmware>=4.60<5.36
Zyxel Vpn300 Firmware=5.36
Zyxel Vpn300 Firmware=5.36-patch1
Zyxel Vpn300
All of
Any of
Zyxel Multiple Network-Attached Storage (NAS) Devices>=4.60<5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36
Zyxel Multiple Network-Attached Storage (NAS) Devices=5.36-patch1
Zyxel Multiple Network-Attached Storage (NAS) Devices
All of
Any of
Zyxel Usg20-vpn Firmware>=4.60<5.36
Zyxel Usg20-vpn Firmware=5.36
Zyxel Usg20-vpn Firmware=5.36-patch1
Zyxel Usg20-vpn
All of
Any of
Zyxel Usg 40 Firmware>=4.60<4.73
Zyxel Usg 40 Firmware=4.73
Zyxel Usg 40 Firmware=4.73-patch1
Zyxel Usg 40
All of
Any of
Zyxel Usg 40w Firmware>=4.60<4.73
Zyxel Usg 40w Firmware=4.73
Zyxel Usg 40w Firmware=4.73-patch1
Zyxel Usg 40w
All of
Any of
Zyxel Usg 60w Firmware>=4.60<4.73
Zyxel Usg 60w Firmware=4.73
Zyxel Usg 60w Firmware=4.73-patch1
Zyxel Usg 60w
All of
Any of
Zyxel Usg 60 Firmware>=4.60<4.73
Zyxel Usg 60 Firmware=4.73
Zyxel Usg 60 Firmware=4.73-patch1
Zyxel Usg 60
Zyxel Multiple Firewalls
All of
Zyxel Atp100
Any of
Zyxel Atp100 Firmware>=4.60<5.36
Zyxel Atp100 Firmware=5.36
Zyxel Atp100 Firmware=5.36-patch1
All of
Any of
Zyxel Vpn1000 Firmware>=4.60<5.36
Zyxel Vpn1000 Firmware=5.36
Zyxel Vpn1000 Firmware=5.36-patch1
Zyxel Vpn1000

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Reference Links

Frequently Asked Questions

  • What is CVE-2023-33009?

    CVE-2023-33009 is a buffer overflow vulnerability in the notification function in Zyxel ATP series, USG FLEX series, USG FLEX 50(W), and USG20(W)-VPN firmware versions 4.32 through 5.36 Patch 1.

  • How does CVE-2023-33009 affect Zyxel Multiple Firewalls?

    CVE-2023-33009 affects Zyxel ATP series, USG FLEX series, USG FLEX 50(W), and USG20(W)-VPN firmware versions 4.32 through 5.36 Patch 1, leading to a buffer overflow vulnerability in the notification function.

  • How severe is CVE-2023-33009?

    CVE-2023-33009 is a buffer overflow vulnerability with a severity rating of high.

  • Is there a patch available for CVE-2023-33009?

    Yes, Zyxel has released firmware versions 5.36 Patch 2 and later to address the CVE-2023-33009 vulnerability.

  • What should I do to fix CVE-2023-33009?

    To fix CVE-2023-33009, update your Zyxel firewall's firmware to version 5.36 Patch 2 or later.

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