CVE-2023-35139

MEDIUM

6.1

CVSS Score

Published: November 28, 2023 at 01:22 AM UTC

Updated: June 17, 2026 at 06:04 AM UTC

25 products affected across 1 vendorZldUsg Flex 200Usg Flex 500

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Severity

MEDIUM6.1

Exploit prediction

EPSS 0.5%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Zld · Zyxel

95%

5.00 ≤ v ≤ 5.375.10 ≤ v ≤ 5.37

zyxel-atp100 (environment) · zyxel-atp100w (environment) · zyxel-atp200 (environment) · zyxel-atp500 (environment) · zyxel-atp700 (environment) · zyxel-atp800 (environment) · zyxel-usg-20w-vpn (environment) · zyxel-usg-flex-100 (environment) · zyxel-usg-flex-100w (environment) · zyxel-usg-flex-200 (environment) · zyxel-usg-flex-50 (environment) · zyxel-usg-flex-500 (environment) · zyxel-usg-flex-50w (environment) · zyxel-usg-flex-700 (environment) · zyxel-vpn100 (environment) · zyxel-vpn1000 (environment) · zyxel-vpn300 (environment) · zyxel-vpn50 (environment) · zyxel-vpn50w (environment)

ATP · Zyxel

60%

v ≤ 5.37

USG FLEX · Zyxel

60%

v ≤ 5.37

Usg Flex 50 · Zyxel

60%

v ≤ 5.37

Usg Flex 50W · Zyxel

60%

v ≤ 5.37