CVE-2021-31228: Hcc-Embedded Nichestack

High severity, CVSS 7.5. EPSS: 1.3% chance of exploitation in the next 30 days.

An issue was discovered in HCC embedded InterNiche 4.0.1. This vulnerability allows the attacker to predict a DNS query's source port in order to send forged DNS response packets that will be accepted as valid answers to the DNS client's requests (without sniffing the specific request). Data is predictable because it is based on the time of day, and has too few bits.

Affected products

• Hcc-Embedded Nichestack: before 4.3 (fixed in 4.3)

Published 2021-08-19. Last modified 2026-06-17.