CVE-2026-23095
In the Linux kernel, the following vulnerability has been resolved:
gue: Fix skb memleak with inner IP protocol 0.
syzbot reported skb memleak below. [0]
The repro generated a GUE packet with its inner protocol 0.
gue_udp_recv() returns -guehdr->proto_ctype for "resubmit" in ip_protocol_deliver_rcu(), but this only works with non-zero protocol number.
Let's drop such packets.
Note that 0 is a valid number (IPv6 Hop-by-Hop Option).
I think it is not practical to encap HOPOPT in GUE, so once someone starts to complain, we could pass down a resubmit flag pointer to distinguish two zeros from the upper layer:
Detalles técnicos trazas, registros y código del informe original
* no error
* resubmit HOPOPT
[0]
BUG: memory leak
unreferenced object 0xffff888109695a00 (size 240):
comm "syz.0.17", pid 6088, jiffies 4294943096
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............
backtrace (crc a84b336f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270
__build_skb+0x23/0x60 net/core/skbuff.c:474
build_skb+0x20/0x190 net/core/skbuff.c:490
__tun_build_skb drivers/net/tun.c:1541 [inline]
tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636
tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770
tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x45d/0x710 fs/read_write.c:686
ksys_write+0xa7/0x170 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7fCVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.28%
- Percentil entre todas las CVEs puntuadas: 19
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-401
Referencias
- https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96a
- https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8f
- https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8c
- https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766
- https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bdded
- https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35
- https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngue: Fix skb memleak with inner IP protocol 0.\n\nsyzbot reported skb memleak below. [0]\n\nThe repro generated a GUE packet with its inner protocol 0.\n\ngue_udp_recv() returns -guehdr->proto_ctype for \"resubmit\"\nin ip_protocol_deliver_rcu(), but this only works with\nnon-zero protocol number.\n\nLet's drop such packets.\n\nNote that 0 is a valid number (IPv6 Hop-by-Hop Option).\n\nI think it is not practical to encap HOPOPT in GUE, so once\nsomeone starts to complain, we could pass down a resubmit\nflag pointer to distinguish two zeros from the upper layer:\n\n * no error\n * resubmit HOPOPT\n\n[0]\nBUG: memory leak\nunreferenced object 0xffff888109695a00 (size 240):\n comm \"syz.0.17\", pid 6088, jiffies 4294943096\n hex dump (first 32 bytes):\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\n 00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............\n backtrace (crc a84b336f):\n kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]\n slab_post_alloc_hook mm/slub.c:4958 [inline]\n slab_alloc_node mm/slub.c:5263 [inline]\n kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270\n __build_skb+0x23/0x60 net/core/skbuff.c:474\n build_skb+0x20/0x190 net/core/skbuff.c:490\n __tun_build_skb drivers/net/tun.c:1541 [inline]\n tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636\n tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770\n tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999\n new_sync_write fs/read_write.c:593 [inline]\n vfs_write+0x45d/0x710 fs/read_write.c:686\n ksys_write+0xa7/0x170 fs/read_write.c:738\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f"
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"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ngue: Corrige la fuga de memoria de skb con el protocolo IP interno 0.\n\nsyzbot informó de una fuga de memoria de skb a continuación. [0]\n\nLa reproducción generó un paquete GUE con su protocolo interno 0.\n\ngue_udp_recv() devuelve -guehdr->proto_ctype para 'resubmit' en ip_protocol_deliver_rcu(), pero esto solo funciona con números de protocolo distintos de cero.\n\nDescartemos tales paquetes.\n\nTenga en cuenta que 0 es un número válido (Opción Salto a Salto de IPv6).\n\nCreo que no es práctico encapsular HOPOPT en GUE, así que una vez que alguien empiece a quejarse, podríamos pasar un puntero de bandera de reenvío para distinguir dos ceros de la capa superior:\n\n * sin error\n * reenviar HOPOPT\n\n[0]\nBUG: fuga de memoria\nobjeto sin referencia 0xffff888109695a00 (tamaño 240):\n comm 'syz.0.17', pid 6088, jiffies 4294943096\n volcado hexadecimal (primeros 32 bytes):\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\n 00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............\n rastreo (crc a84b336f):\n kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]\n slab_post_alloc_hook mm/slub.c:4958 [inline]\n slab_alloc_node mm/slub.c:5263 [inline]\n kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270\n __build_skb+0x23/0x60 net/core/skbuff.c:474\n build_skb+0x20/0x190 net/core/skbuff.c:490\n __tun_build_skb drivers/net/tun.c:1541 [inline]\n tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636\n tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770\n tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999\n new_sync_write fs/read_write.c:593 [inline]\n vfs_write+0x45d/0x710 fs/read_write.c:686\n ksys_write+0xa7/0x170 fs/read_write.c:738\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f"
}
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"lastModified": "2026-07-14T13:18:24.410",
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