CVE-2023-34139

Name: CVE-2023-34139
Creator: NVD / NIST
Published: 2023-07-17T18:15:09.607+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 0.69%

Last modified Jun 17, 2026

CVE-2023-34139 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. A command injection vulnerability in the Free Time WiFi hotspot feature of the Zyxel USG FLEX series firmware versions 4.50 through 5.36 Patch 2 and VPN series firmware versions 4.20 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device.. EPSS estimates a 0.69% chance of exploitation in the next 30 days.

Description

A command injection vulnerability in the Free Time WiFi hotspot feature of the Zyxel USG FLEX series firmware versions 4.50 through 5.36 Patch 2 and VPN series firmware versions 4.20 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

0.69%

48.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zyxel	Usg 2200-Vpn Firmware	>= 4.20, < 5.37
Zyxel	Usg Flex 100 Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 100w Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 200 Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 50 Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 500 Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 50w Firmware	>= 4.50, < 5.37
Zyxel	Usg Flex 700 Firmware	>= 4.50, < 5.37
Zyxel	Zywall Vpn100 Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn2s Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn300 Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn50 Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn 100 Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn 300 Firmware	>= 4.20, < 5.37
Zyxel	Zywall Vpn 50 Firmware	>= 4.20, < 5.37

References

Timeline

Published: Jul 17, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-34139?

How severe is CVE-2023-34139?

CVE-2023-34139 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.69% probability of exploitation in the next 30 days.

How do I fix CVE-2023-34139?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-34139?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST