CVE-2023-22915

Name: CVE-2023-22915
Creator: NVD / NIST
Published: 2023-04-24T17:15:09.69+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.05%

Last modified Jun 17, 2026

CVE-2023-22915 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 1.05% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.05%

60.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
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 50 Firmware	>= 4.50, <= 5.35
Zyxel	Usg Flex 50w Firmware	>= 4.30, <= 5.35
Zyxel	Usg Flex 500 Firmware	>= 4.50, <= 5.35
Zyxel	Usg Flex 700 Firmware	>= 4.50, <= 5.35
Zyxel	Vpn100 Firmware	>= 4.50, <= 5.35
Zyxel	Vpn1000 Firmware	>= 4.50, <= 5.35
Zyxel	Vpn300 Firmware	>= 4.50, <= 5.35
Zyxel	Vpn50 Firmware	>= 4.50, <= 5.35
Zyxel	Usg 20w-Vpn Firmware	>= 4.30, <= 5.35

References

Timeline

Published: Apr 24, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-22915?

How severe is CVE-2023-22915?

CVE-2023-22915 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.05% probability of exploitation in the next 30 days.

How do I fix CVE-2023-22915?

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-2023-22915?

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

Scan your code now

Source: NVD / NIST