CVE-2021-22161: Openwrt

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

In OpenWrt 19.07.x before 19.07.7, when IPv6 is used, a routing loop can occur that generates excessive network traffic between an affected device and its upstream ISP's router. This occurs when a link prefix route points to a point-to-point link, a destination IPv6 address belongs to the prefix and is not a local IPv6 address, and a router advertisement is received with at least one global unique IPv6 prefix for which the on-link flag is set. This affects the netifd and odhcp6c packages.

Affected products

• Openwrt Openwrt: from 19.07.0, up to and including 19.07.6

Published 2021-02-07. Last modified 2026-06-17.