CVE-2026-31684 net: sched: act_csum: validate nested VLAN headers

In the Linux kernel, the following vulnerability has been resolved: net: sched: actcsum: validate nested VLAN headers tcfcsumact walks nested VLAN headers directly from skb-data when an skb still carries in-payload VLAN tags. The current code reads vlan-hvlanencapsulatedproto and then pulls...