CVE-2023-28771

CISA KEV
ACT NOW Priority: 0.00 BB Relevance: 10/100
Published: N/A Modified: N/A First seen: 2026-10-29 Status: pending_score

Description

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.

CISA Known Exploited Vulnerability

Vendor / Product Zyxel — Multiple Firewalls
Date Added 2023-05-31
Remediation Due 2023-06-21
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

Bug Bounty Relevance

10 / 100
✓ Known exploited (KEV)
✓ High exploitation probability

CVSS Score

Unscored

EPSS — Exploitation Probability

99.28%
Raw Score 0.992840
Percentile 99.9%
Date 2026-10-28

Intelligence Sources

kev ref →