CVE-2023-35139

Name: CVE-2023-35139
Creator: NVD / NIST
Published: 2023-11-28T02:15:42.347+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.46%

Last modified Jun 17, 2026

CVE-2023-35139 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. A cross-site scripting (XSS) vulnerability in the CGI program of the Zyxel ATP series firmware versions 5.10 through 5.37, USG FLEX series firmware versions 5.00 through 5.37, USG FLEX 50(W) series firmware versions 5.10 through 5.37, USG20(W)-VPN series firmware versions 5.10 through 5.37, and VPN series firmware versions 5.00 through 5.37, could allow an unauthenticated LAN-based attacker to store malicious scripts in a vulnerable device. A successful XSS attack could then result in the stored malicious scripts being executed to steal cookies when the user visits the specific CGI used for dumping ZTP logs.. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

Description

A cross-site scripting (XSS) vulnerability in the CGI program of the Zyxel ATP series firmware versions 5.10 through 5.37, USG FLEX series firmware versions 5.00 through 5.37, USG FLEX 50(W) series firmware versions 5.10 through 5.37, USG20(W)-VPN series firmware versions 5.10 through 5.37, and VPN series firmware versions 5.00 through 5.37, could allow an unauthenticated LAN-based attacker to store malicious scripts in a vulnerable device. A successful XSS attack could then result in the stored malicious scripts being executed to steal cookies when the user visits the specific CGI used for dumping ZTP logs.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.46%

36.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Zyxel	Zld	>= 5.10, <= 5.37
Zyxel	Zld	>= 5.00, <= 5.37

References

Timeline

Published: Nov 28, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-35139?

How severe is CVE-2023-35139?

CVE-2023-35139 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.

How do I fix CVE-2023-35139?

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-2023-35139?

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

Scan your code now

Source: NVD / NIST