CVE-2023-22915 Memory corruption in USG FLEX 50(W) firmware

High 7.5 Published 24 Apr 2023 Updated 12 Feb 2025

Remote unauthenticated attackers can cause denial of service via crafted HTTP requests if Facebook WiFi is enabled on affected Zyxel USG and VPN devices.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-22915?

CVE-2023-22915 is a high-severity memory corruption vulnerability in Zyxel USG FLEX 50(W) firmware, published on 24 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-120

Which versions are affected by CVE-2023-22915?

It affects 12 products.

Products include Zyxel Usg 20w-Vpn Firmware, Zyxel Usg Flex 100 Firmware, Zyxel Usg Flex 100w Firmware, Zyxel Usg Flex 200 Firmware, Zyxel Usg Flex 500 Firmware, Zyxel Usg Flex 50 Firmware and 6 more.

How do I fix CVE-2023-22915?

No fix has been published for CVE-2023-22915 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2023-22915 being exploited?

There is no known exploitation of CVE-2023-22915 in the wild and no public exploit code.

Sources

Also known as GHSA-qm4q-mvq2-gj2r.