CVE-2026-99066

Description

In the Linux kernel, the following vulnerability has been resolved: can: dev: init_can_skb(): restore skb header initialization Commit 9f10374bb024 (-can: remove private CAN skb headroom infrastructure-) removed the skb_reset_mac_header()/skb_reset_network_header()/ skb_reset_transport_header() calls from init_can_skb(). As a result, RX skbs from alloc_can_skb() and friends again carry mac_header = 0xFFFF. When such an skb reaches packet_rcv_spkt() (SOCK_PACKET), the push length calculation overflows and triggers skb_under_panic -> kernel BUG -> full machine panic. The same issue was originally reported in 2014 on linux-can and fixed by commit 969439016d2c (-can: add missing initialisations in CAN related skbuffs-). packet_rcv_spkt() itself has never been hardened: only packet_rcv() and tpacket_rcv() gained dev_has_header() checks in commit d549699048b4 (-net/packet: fix packet receive on L3 devices without visible hard header-).