Vulnerability Intelligence Report
Zyxel Multiple Firewalls OS Command Injection Vulnerability
CVE-2023-28771
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.
CISA KEV
SSVC: Active Exploitation
Automatable
CVSS Base Score
9.8
CRITICAL
Exploitability:3.9
Impact Score:5.9
EPSS Probability:99.28%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-78 ↗CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Zyxel | ZyWALL/USG series firmware | 4.60 through 4.73 (affected) |
| Zyxel | VPN series firmware | 4.60 through 5.35 (affected) |
| Zyxel | USG FLEX series firmware | 4.60 through 5.35 (affected) |
| Zyxel | ATP series firmware | 4.60 through 5.35 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Zyxel Corporation · Vendor · Taiwan |
| Reserved | 2023-03-23T00:00:00 |
| Published | 2023-04-25T00:00:00 |
| Last Updated | 2025-10-21T23:05:48 |
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