Zyxel Multiple Firewalls Buffer Overflow Vulnerability

Added to KEV
2023-06-05
Federal due date
2023-06-26
Vendor
Zyxel
Product
Multiple Firewalls
EPSS
91.8th percentile (score 0.073, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2023-33010

CISA short description

Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the ID processing function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.