Critical severity9.8CISA KEVNVD Advisory· Published May 24, 2023· Updated Jun 17, 2026

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

Zyxel/Atp100 Firmware3 versions
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp100_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp100_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Atp100w Firmware3 versions
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp100w_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp100w_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Atp200 Firmware3 versions
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp200_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp200_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Atp500 Firmware3 versions
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp500_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp500_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Atp700 Firmware3 versions
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp700_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp700_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Atp800 Firmware3 versions
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:atp800_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:atp800_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg20 VPN Firmware4 versions
cpe:2.3:o:zyxel:usg20-vpn_firmware:*:*:*:*:*:*:*:*+ 3 more
- cpe:2.3:o:zyxel:usg20-vpn_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg20-vpn_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg20-vpn_firmware:5.36:patch1:*:*:*:*:*:*
- (no CPE)range: 4.60 through 5.36 Patch 1
Zyxel/Usg 20w VPN Firmware3 versions
cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_20w-vpn_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_20w-vpn_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg 40 Firmware3 versions
cpe:2.3:o:zyxel:usg_40_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_40_firmware:*:*:*:*:*:*:*:*range: >=4.60,<4.73
- cpe:2.3:o:zyxel:usg_40_firmware:4.73:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_40_firmware:4.73:patch1:*:*:*:*:*:*
Zyxel/Usg 40w Firmware3 versions
cpe:2.3:o:zyxel:usg_40w_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_40w_firmware:*:*:*:*:*:*:*:*range: >=4.60,<4.73
- cpe:2.3:o:zyxel:usg_40w_firmware:4.73:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_40w_firmware:4.73:patch1:*:*:*:*:*:*
Zyxel/Usg 60 Firmware3 versions
cpe:2.3:o:zyxel:usg_60_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_60_firmware:*:*:*:*:*:*:*:*range: >=4.60,<4.73
- cpe:2.3:o:zyxel:usg_60_firmware:4.73:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_60_firmware:4.73:patch1:*:*:*:*:*:*
Zyxel/Usg 60w Firmware3 versions
cpe:2.3:o:zyxel:usg_60w_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_60w_firmware:*:*:*:*:*:*:*:*range: >=4.60,<4.73
- cpe:2.3:o:zyxel:usg_60w_firmware:4.73:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_60w_firmware:4.73:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 100 Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_100_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_100_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 100w Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 200 Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_200_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_200_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 500 Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_500_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_500_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 50 Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_50_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_50_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Usg Flex 50w Firmware4 versions
cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:*+ 3 more
- cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_50w_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_50w_firmware:5.36:patch1:*:*:*:*:*:*
- (no CPE)range: 4.60 - 5.36 Patch 1
Zyxel/Usg Flex 700 Firmware3 versions
cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:usg_flex_700_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:usg_flex_700_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Vpn1000 Firmware3 versions
cpe:2.3:o:zyxel:vpn1000_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:vpn1000_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:vpn1000_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:vpn1000_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Vpn100 Firmware3 versions
cpe:2.3:o:zyxel:vpn100_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:vpn100_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:vpn100_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:vpn100_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Vpn300 Firmware3 versions
cpe:2.3:o:zyxel:vpn300_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:vpn300_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:vpn300_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:vpn300_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/Vpn50 Firmware3 versions
cpe:2.3:o:zyxel:vpn50_firmware:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:o:zyxel:vpn50_firmware:*:*:*:*:*:*:*:*range: >=4.60,<5.36
- cpe:2.3:o:zyxel:vpn50_firmware:5.36:-:*:*:*:*:*:*
- cpe:2.3:o:zyxel:vpn50_firmware:5.36:patch1:*:*:*:*:*:*
Zyxel/ZyWALL/USG series firmwarellm-create
Range: 4.60 - 4.73 Patch 1
Zyxel/ATP series firmwarellm-fuzzy
Range: 4.60 - 5.36 Patch 1
Zyxel/USG FLEX series firmwarellm-fuzzy
Range: 4.60 - 5.36 Patch 1
Zyxel/USG20(W)-VPN series firmwarellm-fuzzy
Range: 4.60 - 5.36 Patch 1
Zyxel/VPN series firmwarellm-fuzzy
Range: 4.60 - 5.36 Patch 1
Zyxel/ATP seriescpe-rescue
Range: 4.60 through 5.36 Patch 1
Zyxel/USG FLEX 50(W)cpe-rescue
Range: 4.60 through 5.36 Patch 1
Zyxel/USG FLEX seriescpe-rescue
Range: 4.60 through 5.36 Patch 1
Zyxel/VPN seriescpe-rescue
Range: 4.60 through 5.36 Patch 1
Zyxel/ZyWALL/USG seriescpe-rescue
Range: 4.60 through 4.73 Patch 1

Patches

Vulnerability mechanics

References

www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewallsnvdVendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalognvdUS Government Resource

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