CVE-2026-31684

In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.

The following products are affected by CVE-2026-31684 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-31684.

URL	Resource
https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5
https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b
https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834
https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62