CVE-2024-56655
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: do not defer rule destruction via call_rcu
nf_tables_chain_destroy can sleep, it can't be used from call_rcu callbacks.
Moreover, nf_tables_rule_release() is only safe for error unwinding, while transaction mutex is held and the to-be-desroyed rule was not exposed to either dataplane or dumps, as it deactives+frees without the required synchronize_rcu() in-between.
nft_rule_expr_deactivate() callbacks will change ->use counters of other chains/sets, see e.g. nft_lookup .deactivate callback, these must be serialized via transaction mutex.
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Also add a few lockdep asserts to make this more explicit.
Calling synchronize_rcu() isn't ideal, but fixing this without is hard and way more intrusive. As-is, we can get:
In case the synchronize_rcu becomes an issue, we can explore alternatives.
One way would be to allocate nft_trans_rule objects + one nft_trans_chain object, deactivate the rules + the chain and then defer the freeing to the nft destroy workqueue. We'd still need to keep the synchronize_rcu path as a fallback to handle -ENOMEM corner cases though.
Detalles técnicos trazas, registros y código del informe original
WARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x.. Workqueue: events nf_tables_trans_destroy_work RIP: 0010:nft_set_destroy+0x3fe/0x5c0 Call Trace: <TASK> nf_tables_trans_destroy_work+0x6b7/0xad0 process_one_work+0x64a/0xce0 worker_thread+0x613/0x10d0
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: 0.22%
- Percentil entre todas las CVEs puntuadas: 12
- 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
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/27f0574253f6c24c8ee4e3f0a685b75ed3a256ed
- https://git.kernel.org/stable/c/2991dc357a28b61c13ed1f7b59e9251e2b4562fb
- https://git.kernel.org/stable/c/5146c27b2780aac59876a887a5f4e793b8949862
- https://git.kernel.org/stable/c/7cf0bd232b565d9852cb25fd094f77254773e048
- https://git.kernel.org/stable/c/b04df3da1b5c6f6dc7cdccc37941740c078c4043
- https://git.kernel.org/stable/c/b0f013bebf94fe7ae75e5a53be2f2bd1cc1841e3
- https://git.kernel.org/stable/c/b8d8f53e1858178882b881b8c09f94ef0e83bf76
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: do not defer rule destruction via call_rcu\n\nnf_tables_chain_destroy can sleep, it can't be used from call_rcu\ncallbacks.\n\nMoreover, nf_tables_rule_release() is only safe for error unwinding,\nwhile transaction mutex is held and the to-be-desroyed rule was not\nexposed to either dataplane or dumps, as it deactives+frees without\nthe required synchronize_rcu() in-between.\n\nnft_rule_expr_deactivate() callbacks will change ->use counters\nof other chains/sets, see e.g. nft_lookup .deactivate callback, these\nmust be serialized via transaction mutex.\n\nAlso add a few lockdep asserts to make this more explicit.\n\nCalling synchronize_rcu() isn't ideal, but fixing this without is hard\nand way more intrusive. As-is, we can get:\n\nWARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x..\nWorkqueue: events nf_tables_trans_destroy_work\nRIP: 0010:nft_set_destroy+0x3fe/0x5c0\nCall Trace:\n <TASK>\n nf_tables_trans_destroy_work+0x6b7/0xad0\n process_one_work+0x64a/0xce0\n worker_thread+0x613/0x10d0\n\nIn case the synchronize_rcu becomes an issue, we can explore alternatives.\n\nOne way would be to allocate nft_trans_rule objects + one nft_trans_chain\nobject, deactivate the rules + the chain and then defer the freeing to the\nnft destroy workqueue. We'd still need to keep the synchronize_rcu path as\na fallback to handle -ENOMEM corner cases though."
},
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"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: nf_tables: no aplazar la destrucción de la regla mediante call_rcu nf_tables_chain_destroy puede dormir, no se puede utilizar desde las devoluciones de llamadas call_rcu. Además, nf_tables_rule_release() solo es seguro para desenrollar errores, mientras se mantiene el mutex de transacción y la regla a destruir no se expuso ni al plano de datos ni a los volcados, ya que desactiva + libera sin elsynchronous_rcu() requerido en el medio. Las devoluciones de llamadas nft_rule_expr_deactivate() cambiarán ->use contadores de otras cadenas/conjuntos, consulte, por ejemplo, la devolución de llamada nft_lookup .deactivate, que se deben serializar mediante el mutex de transacción. Agregue también algunas afirmaciones lockdep para que esto sea más explícito. Llamar asynchronous_rcu() no es ideal, pero solucionar esto sin él es difícil y mucho más intrusivo. Tal como está, podemos obtener: ADVERTENCIA: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x.. Cola de trabajo: eventos nf_tables_trans_destroy_work RIP: 0010:nft_set_destroy+0x3fe/0x5c0 Rastreo de llamadas: nf_tables_trans_destroy_work+0x6b7/0xad0 process_one_work+0x64a/0xce0 worker_thread+0x613/0x10d0 En caso de que elsynchronous_rcu se convierta en un problema, podemos explorar alternativas. Una forma sería asignar objetos nft_trans_rule + un objeto nft_trans_chain, desactivar las reglas + la cadena y luego diferir la liberación a la cola de trabajo de destrucción de nft. Aún así, necesitaríamos mantener la ruta synchronization_rcu como respaldo para gestionar casos especiales de -ENOMEM."
}
],
"lastModified": "2026-08-04T11:22:18.720",
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