How severe is CVE-2023-28771?

CVE-2023-28771 has a CVSS 3.1 base score of 9.8 (CRITICAL). EPSS estimates a 99.3% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2023-28771: Zyxel Multiple Firewalls OS Command Injection

CISA Known Exploited Vulnerabilities

Zyxel Multiple Firewalls OS Command Injection Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2023-05-31

Remediation due

2023-06-21

Required action
Apply updates per vendor instructions.

CISA notes
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

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.

Severity

CVSS 3.1 · CNA9.8 CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impacttotal

Affected Products

Vendor	Product	Affected versions
Zyxel	ZyWALL/USG series firmware	4.60 through 4.73
Zyxel	VPN series firmware	4.60 through 5.35
Zyxel	USG FLEX series firmware	4.60 through 5.35
Zyxel	ATP series firmware	4.60 through 5.35

References

2 Links

Other references

Record Details

Published

2023-04-25

Last updated

2025-10-21

Assigner (CNA)

Zyxel

Credited to

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Related Tool Categories

Tool categories that test for or protect against this vulnerability class.

CWE-78 · OS Command Injection

Application Security Tools Penetration Testing Tools

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.