CVE-2021-47293: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_skbmod: Skip non-Ethernet packets Currently tcf_skbmod_act() assumes that packets use Ethernet as their L2 protocol, which is not always the case. As an example, for CAN devices: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocol ip prio 10 \ matchall action skbmod swap mac Doing the above silently corrupts all the packets. Do not perform skbmod actions for non-Ethernet packets.

Affected products

• Linux Linux Kernel: from 4.9, before 4.19.199 (fixed in 4.19.199); from 4.20, before 5.4.136 (fixed in 5.4.136); from 5.5, before 5.10.54 (fixed in 5.10.54); from 5.11, before 5.13.6 (fixed in 5.13.6); version 5.14 only

Published 2024-05-21. Last modified 2026-06-17.