CVE-2020-17467: Butok Fnet

Critical severity, CVSS 9.1. EPSS: 3.1% chance of exploitation in the next 30 days.

An issue was discovered in FNET through 4.6.4. The code for processing the hostname from an LLMNR request doesn't check for '\0' termination. Therefore, the deduced length of the hostname doesn't reflect the correct length of the actual data. This may lead to Information Disclosure in _fnet_llmnr_poll in fnet_llmnr.c during a response to a malicious request of the DNS class IN.

Affected products

• Butok Fnet: up to and including 4.6.4

Published 2020-12-11. Last modified 2026-06-17.