{"cve":"CVE-2026-23003","nvd":{"published":"2026-01-25T15:15:55.170","modified":"2026-10-19T19:17:31.927","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()\n\nBlamed commit did not take care of VLAN encapsulations\nas spotted by syzbot [1].\n\nUse skb_vlan_inet_prepare() instead of pskb_inet_may_pull().\n\n[1]\n BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]\n BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]\n BUG: KMSAN: uninit-value in IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321\n  __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]\n  INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]\n  IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321\n  ip6ip6_dscp_ecn_decapsulate+0x16f/0x1b0 net/ipv6/ip6_tunnel.c:729\n  __ip6_tnl_rcv+0xed9/0x1b50 net/ipv6/ip6_tunnel.c:860\n  ip6_tnl_rcv+0xc3/0x100 net/ipv6/ip6_tunnel.c:903\n gre_rcv+0x1529/0x1b90 net/ipv6/ip6_gre.c:-1\n  ip6_protocol_deliver_rcu+0x1c89/0x2c60 net/ipv6/ip6_input.c:438\n  ip6_input_finish+0x1f4/0x4a0 net/ipv6/ip6_input.c:489\n  NF_HOOK include/linux/netfilter.h:318 [inline]\n  ip6_input+0x9c/0x330 net/ipv6/ip6_input.c:500\n  ip6_mc_input+0x7ca/0xc10 net/ipv6/ip6_input.c:590\n  dst_input include/net/dst.h:474 [inline]\n  ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79\n  NF_HOOK include/linux/netfilter.h:318 [inline]\n  ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311\n  __netif_receive_skb_one_core net/core/dev.c:6139 [inline]\n  __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252\n  netif_receive_skb_internal net/core/dev.c:6338 [inline]\n  netif_receive_skb+0x57/0x630 net/core/dev.c:6397\n  tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485\n  tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953\n  tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999\n  new_sync_write fs/read_write.c:593 [inline]\n  vfs_write+0xbe2/0x15d0 fs/read_write.c:686\n  ksys_write fs/read_write.c:738 [inline]\n  __do_sys_write fs/read_write.c:749 [inline]\n  __se_sys_write fs/read_write.c:746 [inline]\n  __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746\n  x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2\n  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n  do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nUninit was created at:\n  slab_post_alloc_hook mm/slub.c:4960 [inline]\n  slab_alloc_node mm/slub.c:5263 [inline]\n  kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315\n  kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586\n  __alloc_skb+0x805/0x1040 net/core/skbuff.c:690\n  alloc_skb include/linux/skbuff.h:1383 [inline]\n  alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712\n  sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995\n  tun_alloc_skb drivers/net/tun.c:1461 [inline]\n  tun_get_user+0x1142/0x6c60 drivers/net/tun.c:1794\n  tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999\n  new_sync_write fs/read_write.c:593 [inline]\n  vfs_write+0xbe2/0x15d0 fs/read_write.c:686\n  ksys_write fs/read_write.c:738 [inline]\n  __do_sys_write fs/read_write.c:749 [inline]\n  __se_sys_write fs/read_write.c:746 [inline]\n  __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746\n  x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2\n  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n  do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCPU: 0 UID: 0 PID: 6465 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-908","CWE-457"],"references":["https://git.kernel.org/stable/c/2f03dafea0a8096a2eb60f551218b360e5bab9a3","https://git.kernel.org/stable/c/64c71d60a21a9ed0a802483dcd422b5b24eb1abe","https://git.kernel.org/stable/c/81c734dae203757fb3c9eee6f9896386940776bd","https://git.kernel.org/stable/c/9e1c8c2a33d0a7b1f637b5d0602fe56ed10166af","https://git.kernel.org/stable/c/b9f915340f25cae1562f18e1eb52deafca328414"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-23003","score":0.00547,"percentile":0.45587,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}