CRITICAL🚩 CISA KEV⚡ EXPLOIT✓ PATCH🇵🇱 Wersja polska

CVE-2023-28771

CVSS 9.8v3.1pub. 2023-04-25upd. 2025-10-27

Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware versions 4.60 through 5.35, USG FLEX series firmware versions 4.60 through 5.35, and ATP series firmware versions 4.60 through 5.35, which could allow an unauthenticated attacker to execute some OS commands remotely by sending crafted packets to an affected device.

🇵🇱 Read Polish description →

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Zyxel Atp100
HW
Zyxel
all versions
Zyxel Atp100 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Atp100w
HW
Zyxel
all versions
Zyxel Atp100w Firmware
OS
Zyxel
4.60 – 5.35 (excl.)
Zyxel Atp200
HW
Zyxel
all versions
Zyxel Atp200 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Atp500
HW
Zyxel
all versions
Zyxel Atp500 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Atp700
HW
Zyxel
all versions
Zyxel Atp700 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Atp800
HW
Zyxel
all versions
Zyxel Atp800 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 100
HW
Zyxel
all versions
Zyxel Usg Flex 100 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 100w
HW
Zyxel
all versions
Zyxel Usg Flex 100w Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 200
HW
Zyxel
all versions
Zyxel Usg Flex 200 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 50
HW
Zyxel
all versions
Zyxel Usg Flex 500
HW
Zyxel
all versions
Zyxel Usg Flex 500 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 50 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 50w
HW
Zyxel
all versions
Zyxel Usg Flex 50w Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Usg Flex 700
HW
Zyxel
all versions
Zyxel Usg Flex 700 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Vpn100
HW
Zyxel
all versions
Zyxel Vpn1000
HW
Zyxel
all versions
Zyxel Vpn1000 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)
Zyxel Vpn100 Firmware
OS
Zyxel
4.60 – 5.36 (excl.)

CISA KEV — detailsi

Vendori: Zyxel
Producti: Multiple Firewalls
Added to KEVi: May 31, 2023
Remediation deadline (US Federal)i: June 21, 2023(overdue)

🇺🇸CISA KEV (original)↗

Required action (CISA)i

Apply updates per vendor instructions.

CISA descriptioni

Zyxel ATP, USG FLEX, VPN, and ZyWALL/USG firewalls allow for improper error message handling which could allow an unauthenticated attacker to execute OS commands remotely by sending crafted packets to an affected device.

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