Critical (9.8) in Zyxel Multiple Firewalls. In CISA KEV since 2023-05-31. EPSS 99% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
99% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)