CVE-2023-28771
Published 2023-04-25 · Updated 2026-06-17 · Source security@zyxel.com.tw
Summary
CVE-2023-28771 is a critical-severity (CVSS 9.8) vulnerability in Zyxel Multiple Firewalls. CISA added it to the Known Exploited Vulnerabilities catalog on May 31, 2023, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by June 21, 2023. CISA does not currently list it as used in ransomware campaigns. Zyxel has 13 vulnerabilities in the KEV catalog, 2 of them linked to ransomware.
All 13 known-exploited Zyxel vulnerabilities →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.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA Known-Exploited Vulnerability
Product: Zyxel — Multiple Firewalls
Name: Zyxel Multiple Firewalls OS Command Injection Vulnerability
Date added: 2023-05-31 · Due: 2023-06-21
Required action: Apply updates per vendor instructions.
References
- http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls
- http://packetstormsecurity.com/files/172820/Zyxel-IKE-Packet-Decoder-Unauthenticated-Remote-Code-Execution.html
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28771