CVE-2021-38311: Contiki-OS Contiki

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

In Contiki 3.0, potential nonterminating acknowledgment loops exist in the Telnet service. When the negotiated options are already disabled, servers still respond to DONT and WONT requests with WONT or DONT commands, which may lead to infinite acknowledgment loops, denial of service, and excessive CPU consumption.

Affected products

• Contiki-OS Contiki: version 3.0 only

Published 2021-08-09. Last modified 2026-06-17.