CVEvulnerability

CVE-2023-28771

9.8 CRITICAL Known exploited Published 2023-04-25 Modified 2026-06-17 Official page ↗

CISA Known Exploited Vulnerability

Zyxel Multiple Firewalls OS Command Injection Vulnerability — Zyxel Multiple Firewalls

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.

Added to KEV: 2023-05-31
Remediation due: 2023-06-21
Ransomware use: Unknown
Required action: Apply updates per vendor instructions.
Notes: https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls; https://nvd.nist.gov/vuln/detail/CVE-2023-28771

Status: Analyzed
Published: 2023-04-25
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-78

Description

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.

Affected configurations

• zyxel atp100 firmware (>= 4.60 < 5.36) • zyxel atp100w firmware (>= 4.60 < 5.35) • zyxel atp200 firmware (>= 4.60 < 5.36) • zyxel atp500 firmware (>= 4.60 < 5.36) • zyxel atp700 firmware (>= 4.60 < 5.36) • zyxel atp800 firmware (>= 4.60 < 5.36) • zyxel usg flex 100 firmware (>= 4.60 < 5.36) • zyxel usg flex 100w firmware (>= 4.60 < 5.36) • zyxel usg flex 200 firmware (>= 4.60 < 5.36) • zyxel usg flex 50 firmware (>= 4.60 < 5.36) • zyxel usg flex 500 firmware (>= 4.60 < 5.36) • zyxel usg flex 50w firmware (>= 4.60 < 5.36) • zyxel usg flex 700 firmware (>= 4.60 < 5.36) • zyxel vpn100 firmware (>= 4.60 < 5.36) • zyxel vpn1000 firmware (>= 4.60 < 5.36) • zyxel vpn300 firmware (>= 4.60 < 5.36) • zyxel vpn50 firmware (>= 4.60 < 5.36) • zyxel zywall usg 310 firmware (>= 4.60 < 4.73) • zyxel zywall usg 310 firmware 4.73 • zyxel zywall usg 100 firmware (>= 4.60 < 4.73) • zyxel zywall usg 100 firmware 4.73

Weakness · CWE (1)

CWE-78 Improper Neutralization of Special Elements used in an OS Command weakness

References