CVE-2023-22915: zyxel usg_20w-vpn_firmware Classic Buffer Overflow

Vulnerability summary

CVE-2023-22915 is a high (CVSS 7.5) Classic Buffer Overflow vulnerability in zyxel usg_20w-vpn_firmware. EPSS estimates a 1.05% chance of exploitation in the next 30 days, higher than 63.9% of scored vulnerabilities.

Timeline

1. 24-04-2023
   PublishedVulnerability first disclosed.
2. 12-02-2025
   Last modifiedVulnerability information updated.

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.

• CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.