CVE-2023-22915 | BDVDB-2026-200847 Detail

ZyxelUSG FLEX series firmware

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.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact high. Attack vector: network.

Weaknesses#

CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

References#

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

Exploit#

No public exploit known

History#

Version 12023-04-24Record published in the CVE List.
Version 22025-02-12Most recent update recorded in the CVE List.

Published

Published: 2023-04-24
Last modified: 2025-02-12

Vendor information

Vendor: Zyxel
Product: USG FLEX series firmware

All Zyxel vulnerabilities

Score

7.5 High

EPSS

1.0%, Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 64.6.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Memory Corruption

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
4.50 through 5.35
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.5 High

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	None
Integrity	None
Availability	High

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).