CVE-2025-21891

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ipvlan: ensure network headers are in skb linear part<br /> <br /> syzbot found that ipvlan_process_v6_outbound() was assuming<br /> the IPv6 network header isis present in skb-&gt;head [1]<br /> <br /> Add the needed pskb_network_may_pull() calls for both<br /> IPv4 and IPv6 handlers.<br /> <br /> [1]<br /> BUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47<br /> __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47<br /> ipv6_addr_type include/net/ipv6.h:555 [inline]<br /> ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline]<br /> ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651<br /> ip6_route_output include/net/ip6_route.h:93 [inline]<br /> ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476<br /> ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline]<br /> ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline]<br /> ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline]<br /> ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671<br /> ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223<br /> __netdev_start_xmit include/linux/netdevice.h:5150 [inline]<br /> netdev_start_xmit include/linux/netdevice.h:5159 [inline]<br /> xmit_one net/core/dev.c:3735 [inline]<br /> dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751<br /> sch_direct_xmit+0x399/0xd40 net/sched/sch_generic.c:343<br /> qdisc_restart net/sched/sch_generic.c:408 [inline]<br /> __qdisc_run+0x14da/0x35d0 net/sched/sch_generic.c:416<br /> qdisc_run+0x141/0x4d0 include/net/pkt_sched.h:127<br /> net_tx_action+0x78b/0x940 net/core/dev.c:5484<br /> handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:561<br /> __do_softirq+0x14/0x1a kernel/softirq.c:595<br /> do_softirq+0x9a/0x100 kernel/softirq.c:462<br /> __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:389<br /> local_bh_enable include/linux/bottom_half.h:33 [inline]<br /> rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]<br /> __dev_queue_xmit+0x2758/0x57d0 net/core/dev.c:4611<br /> dev_queue_xmit include/linux/netdevice.h:3311 [inline]<br /> packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276<br /> packet_snd net/packet/af_packet.c:3132 [inline]<br /> packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164<br /> sock_sendmsg_nosec net/socket.c:718 [inline]