CVE-2026-23003 (GCVE-0-2026-23003)

Vulnerability from cvelistv5 – Published: 2026-01-25 14:36 – Updated: 2026-09-08 08:44
VLAI
Title
ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()
Summary
In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() Blamed commit did not take care of VLAN encapsulations as spotted by syzbot [1]. Use skb_vlan_inet_prepare() instead of pskb_inet_may_pull(). [1] BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] BUG: KMSAN: uninit-value in IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 ip6ip6_dscp_ecn_decapsulate+0x16f/0x1b0 net/ipv6/ip6_tunnel.c:729 __ip6_tnl_rcv+0xed9/0x1b50 net/ipv6/ip6_tunnel.c:860 ip6_tnl_rcv+0xc3/0x100 net/ipv6/ip6_tunnel.c:903 gre_rcv+0x1529/0x1b90 net/ipv6/ip6_gre.c:-1 ip6_protocol_deliver_rcu+0x1c89/0x2c60 net/ipv6/ip6_input.c:438 ip6_input_finish+0x1f4/0x4a0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x9c/0x330 net/ipv6/ip6_input.c:500 ip6_mc_input+0x7ca/0xc10 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6139 [inline] __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252 netif_receive_skb_internal net/core/dev.c:6338 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6397 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4960 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586 __alloc_skb+0x805/0x1040 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995 tun_alloc_skb drivers/net/tun.c:1461 [inline] tun_get_user+0x1142/0x6c60 drivers/net/tun.c:1794 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6465 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-16 20:17 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a9bc32879a08f23cdb80a48c738017e39aea1080 , < f9c5c5b791d3850570796f9e067629474e613796 (git)
Affected: af6b5c50d47ab43e5272ad61935d0ed2e264d3f0 , < 64c71d60a21a9ed0a802483dcd422b5b24eb1abe (git)
Affected: d54e4da98bbfa8c257bdca94c49652d81d18a4d8 , < 9e1c8c2a33d0a7b1f637b5d0602fe56ed10166af (git)
Affected: 350a6640fac4b53564ec20aa3f4a0922cb0ba5e6 , < 2f03dafea0a8096a2eb60f551218b360e5bab9a3 (git)
Affected: 8d975c15c0cd744000ca386247432d57b21f9df0 , < df5ffde9669314500809bc498ae73d6d3d9519ac (git)
Affected: 8d975c15c0cd744000ca386247432d57b21f9df0 , < b9f915340f25cae1562f18e1eb52deafca328414 (git)
Affected: 8d975c15c0cd744000ca386247432d57b21f9df0 , < 81c734dae203757fb3c9eee6f9896386940776bd (git)
Affected: c835df3bcc14858ae9b27315dd7de76370b94f3a (git)
Affected: 5.10.210 , < 5.10.249 (semver)
Affected: 5.15.149 , < 5.15.199 (semver)
Affected: 6.1.77 , < 6.1.162 (semver)
Affected: 6.6.16 , < 6.6.122 (semver)
Affected: 6.7.4 , < 6.8 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 5.10.249 , ≤ 5.10.* (semver)
Unaffected: 5.15.199 , ≤ 5.15.* (semver)
Unaffected: 6.1.162 , ≤ 6.1.* (semver)
Unaffected: 6.6.122 , ≤ 6.6.* (semver)
Unaffected: 6.12.67 , ≤ 6.12.* (semver)
Unaffected: 6.18.7 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP Affected: V3.1.6 , < * (custom)
guessed Create a notification for this product.
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP Affected: V3.1.6 , < * (custom)
guessed Create a notification for this product.
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP Affected: V3.1.6 , < * (custom)
guessed Create a notification for this product.
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          "value": "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"
        }
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              "value": "AV:N - __ip6_tnl_rcv() is reached from IPv6 packet receive via registered IPv6 tunnel/GRE protocol handlers, so a remote peer can trigger it by sending crafted tunneled IPv6/GRE packets to an exposed tunnel endpoint.\nAC:L - The attacker controls the tunneled packet format, including VLAN encapsulation, and there is no race or hard-to-hit timing condition.\nPR:N - Tunnel setup is privileged, but once the affected tunnel endpoint exists, the packet receive path has no attacker credential or authentication requirement.\nUI:N - Processing occurs automatically on packet receipt and does not require any victim user action.\nS:U - The bug affects kernel packet processing within the same host security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - The bug is an uninitialized value use in ECN decapsulation, but the investigated path does not expose the uninitialized kernel data to the attacker.\nI:N - The malformed packet can affect ECN/DSCP handling for that packet, but there is no evidence of arbitrary data modification or control-flow corruption.\nA:H - The reachable KMSAN BUG/oops path demonstrates that crafted packets can trigger a kernel fault condition, which is scored as high availability impact."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        },
        {
          "url": "https://git.kernel.org/stable/c/81c734dae203757fb3c9eee6f9896386940776bd"
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      "title": "ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()",
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        "descriptions": [
          {
            "lang": "en",
            "value": "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"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nip6_tunnel: usar skb_vlan_inet_prepare() en __ip6_tnl_rcv()\n\nEl commit culpable no tuvo en cuenta las encapsulaciones VLAN como fue detectado por syzbot [1].\n\nUsar skb_vlan_inet_prepare() en lugar de pskb_inet_may_pull().\n\n[1]\n ERROR: KMSAN: valor no inicializado en __INET_ECN_decapsulate include/net/inet_ecn.h:253 [en l\u00ednea]\n ERROR: KMSAN: valor no inicializado en INET_ECN_decapsulate include/net/inet_ecn.h:275 [en l\u00ednea]\n ERROR: KMSAN: valor no inicializado en IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321\n  __INET_ECN_decapsulate include/net/inet_ecn.h:253 [en l\u00ednea]\n  INET_ECN_decapsulate include/net/inet_ecn.h:275 [en l\u00ednea]\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 [en l\u00ednea]\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 [en l\u00ednea]\n  ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79\n  NF_HOOK include/linux/netfilter.h:318 [en l\u00ednea]\n  ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311\n  __netif_receive_skb_one_core net/core/dev.c:6139 [en l\u00ednea]\n  __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252\n  netif_receive_skb_internal net/core/dev.c:6338 [en l\u00ednea]\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 [en l\u00ednea]\n  vfs_write+0xbe2/0x15d0 fs/read_write.c:686\n  ksys_write fs/read_write.c:738 [en l\u00ednea]\n  __do_sys_write fs/read_write.c:749 [en l\u00ednea]\n  __se_sys_write fs/read_write.c:746 [en l\u00ednea]\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 [en l\u00ednea]\n  do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nEl valor no inicializado fue creado en:\n  slab_post_alloc_hook mm/slub.c:4960 [en l\u00ednea]\n  slab_alloc_node mm/slub.c:5263 [en l\u00ednea]\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 [en l\u00ednea]\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 [en l\u00ednea]\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 [en l\u00ednea]\n  vfs_write+0xbe2/0x15d0 fs/read_write.c:686\n  ksys_write fs/read_write.c:738 [en l\u00ednea]\n  __do_sys_write fs/read_write.c:749 [en l\u00ednea]\n  __se_sys_write fs/read_write.c:746 [en l\u00ednea]\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 [en l\u00ednea]\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 No contaminado syzkaller #0 PREEMPT(none)\nNombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 25/10/2025"
          }
        ],
        "id": "CVE-2026-23003",
        "lastModified": "2026-07-14T13:18:21.990",
        "metrics": {
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
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                "value": "CWE-908"
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    },
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      "current_release_date": "2026-09-01T14:16:02+00:00",
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                ]
              },
              {
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                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-09-08T08:44:33.646Z",
              "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
              "shortName": "siemens-SADP"
            },
            "references": [
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              }
            ],
            "x_adpType": "supplier"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
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                    "options": [
                      {
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                      },
                      {
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                      },
                      {
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                      }
                    ],
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              }
            ],
            "providerMetadata": {
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              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/ipv6/ip6_tunnel.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
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                },
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                  "versionType": "semver"
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                },
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                }
              ]
            },
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              "vendor": "Linux",
              "versions": [
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                },
                {
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                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
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                  "status": "unaffected",
                  "version": "5.10.249",
                  "versionType": "semver"
                },
                {
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                },
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                {
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                {
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                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.19",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
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              "nodes": [
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                      "vulnerable": true
                    },
                    {
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            {
              "lang": "en",
              "value": "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"
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - __ip6_tnl_rcv() is reached from IPv6 packet receive via registered IPv6 tunnel/GRE protocol handlers, so a remote peer can trigger it by sending crafted tunneled IPv6/GRE packets to an exposed tunnel endpoint.\nAC:L - The attacker controls the tunneled packet format, including VLAN encapsulation, and there is no race or hard-to-hit timing condition.\nPR:N - Tunnel setup is privileged, but once the affected tunnel endpoint exists, the packet receive path has no attacker credential or authentication requirement.\nUI:N - Processing occurs automatically on packet receipt and does not require any victim user action.\nS:U - The bug affects kernel packet processing within the same host security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - The bug is an uninitialized value use in ECN decapsulation, but the investigated path does not expose the uninitialized kernel data to the attacker.\nI:N - The malformed packet can affect ECN/DSCP handling for that packet, but there is no evidence of arbitrary data modification or control-flow corruption.\nA:H - The reachable KMSAN BUG/oops path demonstrates that crafted packets can trigger a kernel fault condition, which is scored as high availability impact."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T12:20:05.561Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/f9c5c5b791d3850570796f9e067629474e613796"
            },
            {
              "url": "https://git.kernel.org/stable/c/64c71d60a21a9ed0a802483dcd422b5b24eb1abe"
            },
            {
              "url": "https://git.kernel.org/stable/c/9e1c8c2a33d0a7b1f637b5d0602fe56ed10166af"
            },
            {
              "url": "https://git.kernel.org/stable/c/2f03dafea0a8096a2eb60f551218b360e5bab9a3"
            },
            {
              "url": "https://git.kernel.org/stable/c/df5ffde9669314500809bc498ae73d6d3d9519ac"
            },
            {
              "url": "https://git.kernel.org/stable/c/b9f915340f25cae1562f18e1eb52deafca328414"
            },
            {
              "url": "https://git.kernel.org/stable/c/81c734dae203757fb3c9eee6f9896386940776bd"
            }
          ],
          "title": "ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2026-23003",
        "datePublished": "2026-01-25T14:36:17.491Z",
        "dateReserved": "2026-01-13T15:37:45.939Z",
        "dateUpdated": "2026-09-08T08:44:33.646Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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