CVE-2026-23381
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: fix nd_tbl NULL dereference when IPv6 is disabled
When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never initialized because inet6_init() exits before ndisc_init() is called which initializes it. Then, if neigh_suppress is enabled and an ICMPv6 Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() will dereference ipv6_stub->nd_tbl which is NULL, passing it to neigh_lookup(). This causes a kernel NULL pointer dereference.
Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in the callers. This is in essence disabling NS/NA suppression when IPv6 is disabled.
Detalles técnicos trazas, registros y código del informe original
BUG: kernel NULL pointer dereference, address: 0000000000000268 Oops: 0000 [#1] PREEMPT SMP NOPTI [...] RIP: 0010:neigh_lookup+0x16/0xe0 [...] Call Trace: <IRQ> ? neigh_lookup+0x16/0xe0 br_do_suppress_nd+0x160/0x290 [bridge] br_handle_frame_finish+0x500/0x620 [bridge] br_handle_frame+0x353/0x440 [bridge] __netif_receive_skb_core.constprop.0+0x298/0x1110 __netif_receive_skb_one_core+0x3d/0xa0 process_backlog+0xa0/0x140 __napi_poll+0x2c/0x170 net_rx_action+0x2c4/0x3a0 handle_softirqs+0xd0/0x270 do_softirq+0x3f/0x60
CVSS
- 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: 0.12%
- Percentil entre todas las CVEs puntuadas: 2
- 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-476
Referencias
- https://git.kernel.org/stable/c/20ef5c25422f97dd09d751e5ae6c18406cdc78e6
- https://git.kernel.org/stable/c/33dec6f10777d5a8f71c0a200f690da5ae3c2e55
- https://git.kernel.org/stable/c/7a894eb5de246d79f13105c55a67381039a24d44
- https://git.kernel.org/stable/c/a12cdaa3375f0bd3c8f4e564be7c143529abfe5b
- https://git.kernel.org/stable/c/a5c56e65b685360dd3f2278aeff8c21061feb665
- https://git.kernel.org/stable/c/a9d712ccfeef737c0e700a4b5b98f310e07b6b60
- https://git.kernel.org/stable/c/aa73deb3b6b730ec280d45b3f423bfa9e17bc122
- https://git.kernel.org/stable/c/e5e890630533bdc15b26a34bb8e7ef539bdf1322
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix nd_tbl NULL dereference when IPv6 is disabled\n\nWhen booting with the 'ipv6.disable=1' parameter, the nd_tbl is never\ninitialized because inet6_init() exits before ndisc_init() is called\nwhich initializes it. Then, if neigh_suppress is enabled and an ICMPv6\nNeighbor Discovery packet reaches the bridge, br_do_suppress_nd() will\ndereference ipv6_stub->nd_tbl which is NULL, passing it to\nneigh_lookup(). This causes a kernel NULL pointer dereference.\n\n BUG: kernel NULL pointer dereference, address: 0000000000000268\n Oops: 0000 [#1] PREEMPT SMP NOPTI\n [...]\n RIP: 0010:neigh_lookup+0x16/0xe0\n [...]\n Call Trace:\n <IRQ>\n ? neigh_lookup+0x16/0xe0\n br_do_suppress_nd+0x160/0x290 [bridge]\n br_handle_frame_finish+0x500/0x620 [bridge]\n br_handle_frame+0x353/0x440 [bridge]\n __netif_receive_skb_core.constprop.0+0x298/0x1110\n __netif_receive_skb_one_core+0x3d/0xa0\n process_backlog+0xa0/0x140\n __napi_poll+0x2c/0x170\n net_rx_action+0x2c4/0x3a0\n handle_softirqs+0xd0/0x270\n do_softirq+0x3f/0x60\n\nFix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in\nthe callers. This is in essence disabling NS/NA suppression when IPv6 is\ndisabled."
},
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"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: bridge: corrige la desreferencia NULL de nd_tbl cuando IPv6 está deshabilitado\n\nAl arrancar con el parámetro 'ipv6.disable=1', el nd_tbl nunca se inicializa porque inet6_init() sale antes de que se llame a ndisc_init(), que es quien lo inicializa. Luego, si neigh_suppress está habilitado y un paquete ICMPv6 Neighbor Discovery llega al puente, br_do_suppress_nd() desreferenciará ipv6_stub->nd_tbl, que es NULL, pasándolo a neigh_lookup(). Esto causa una desreferencia de puntero NULL del kernel.\n\n BUG: desreferencia de puntero NULL del kernel, dirección: 0000000000000268\n Oops: 0000 [#1] PREEMPT SMP NOPTI\n [...]\n RIP: 0010:neigh_lookup+0x16/0xe0\n [...]\n Rastro de Llamada:\n \n ? neigh_lookup+0x16/0xe0\n br_do_suppress_nd+0x160/0x290 [bridge]\n br_handle_frame_finish+0x500/0x620 [bridge]\n br_handle_frame+0x353/0x440 [bridge]\n __netif_receive_skb_core.constprop.0+0x298/0x1110\n __netif_receive_skb_one_core+0x3d/0xa0\n process_backlog+0xa0/0x140\n __napi_poll+0x2c/0x170\n net_rx_action+0x2c4/0x3a0\n handle_softirqs+0xd0/0x270\n do_softirq+0x3f/0x60\n\nSoluciona esto reemplazando la llamada a IS_ENABLED(IPV6) con ipv6_mod_enabled() en los llamadores. Esto es, en esencia, deshabilitar la supresión de NS/NA cuando IPv6 está deshabilitado."
}
],
"lastModified": "2026-07-14T13:18:31.910",
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