CVE-2023-22915

HIGH

Zyxel Usg Flex 100 Firmware < 5.35 - Buffer Overflow

Title source: rule

Description

A buffer overflow vulnerability in the “fbwifi_forward.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.30 through 5.35, USG20(W)-VPN firmware versions 4.30 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote unauthenticated attacker to cause DoS conditions by sending a crafted HTTP request if the Facebook WiFi function were enabled on an affected device.

References (1)

Core 1

Core References

Vendor Advisory

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-of-firewalls-and-aps

Scores

CVSS v3 7.5

EPSS 0.0108

EPSS Percentile 77.9%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-120

Status published

Products (12)

zyxel/usg_20w-vpn_firmware 4.30 - 5.35

zyxel/usg_flex_100_firmware 4.50 - 5.35

zyxel/usg_flex_100w_firmware 4.50 - 5.35

zyxel/usg_flex_200_firmware 4.50 - 5.35

zyxel/usg_flex_500_firmware 4.50 - 5.35

zyxel/usg_flex_50_firmware 4.50 - 5.35

zyxel/usg_flex_50w_firmware 4.30 - 5.35

zyxel/usg_flex_700_firmware 4.50 - 5.35

zyxel/vpn1000_firmware 4.50 - 5.35

zyxel/vpn100_firmware 4.50 - 5.35

... and 2 more

Published Apr 24, 2023

Tracked Since Feb 18, 2026