CVE-2026-74743

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the macvlan module where devices inherit hard header len from the lower device during macvlan init() but fail to inherit needed headroom and needed tailroom, leaving them set to 0. When the underlying lower device requires extra space for headers or trailers—such as in macsec, ipsec, wireguard, tunnels, or veth with rx headroom—upper layers may fail to reserve sufficient space. This can lead to reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes (a condition where the system attempts to access memory after it has been freed) when dev hard header() or macvlan hard header() prepends header data or when lower devices append tailroom.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.