CVE-2026-22979
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
net: fix memory leak in skb_segment_list for GRO packets
When skb_segment_list() is called during packet forwarding, it handles packets that were aggregated by the GRO engine.
Historically, the segmentation logic in skb_segment_list assumes that individual segments are split from a parent SKB and may need to carry their own socket memory accounting. Accordingly, the code transfers truesize from the parent to the newly created segments.
Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this truesize subtraction in skb_segment_list() was valid because fragments still carry a reference to the original socket.
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However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed this behavior by ensuring that fraglist entries are explicitly orphaned (skb->sk = NULL) to prevent illegal orphaning later in the stack. This change meant that the entire socket memory charge remained with the head SKB, but the corresponding accounting logic in skb_segment_list() was never updated.
As a result, the current code unconditionally adds each fragment's truesize to delta_truesize and subtracts it from the parent SKB. Since the fragments are no longer charged to the socket, this subtraction results in an effective under-count of memory when the head is freed. This causes sk_wmem_alloc to remain non-zero, preventing socket destruction and leading to a persistent memory leak.
The leak can be observed via KMEMLEAK when tearing down the networking environment:
Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST packets constructed by GRO, the truesize adjustment is removed.
The call to skb_release_head_state() must be preserved. As documented in commit cf673ed0e057 ("net: fix fraglist segmentation reference count leak"), it is still required to correctly drop references to SKB extensions that may be overwritten during __copy_skb_header().
Detalles técnicos trazas, registros y código del informe original
unreferenced object 0xffff8881e6eb9100 (size 2048):
comm "ping", pid 6720, jiffies 4295492526
backtrace:
kmem_cache_alloc_noprof+0x5c6/0x800
sk_prot_alloc+0x5b/0x220
sk_alloc+0x35/0xa00
inet6_create.part.0+0x303/0x10d0
__sock_create+0x248/0x640
__sys_socket+0x11b/0x1d0CVSS
- 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: 0.14%
- Percentil entre todas las CVEs puntuadas: 3
- 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/0b27828ebd1ed3107d7929c3737adbe862e99e74
- https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77
- https://git.kernel.org/stable/c/3264881431e308b9c72cb8a0159d57a56d67dd79
- https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab
- https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd
- 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\nnet: fix memory leak in skb_segment_list for GRO packets\n\nWhen skb_segment_list() is called during packet forwarding, it handles\npackets that were aggregated by the GRO engine.\n\nHistorically, the segmentation logic in skb_segment_list assumes that\nindividual segments are split from a parent SKB and may need to carry\ntheir own socket memory accounting. Accordingly, the code transfers\ntruesize from the parent to the newly created segments.\n\nPrior to commit ed4cccef64c1 (\"gro: fix ownership transfer\"), this\ntruesize subtraction in skb_segment_list() was valid because fragments\nstill carry a reference to the original socket.\n\nHowever, commit ed4cccef64c1 (\"gro: fix ownership transfer\") changed\nthis behavior by ensuring that fraglist entries are explicitly\norphaned (skb->sk = NULL) to prevent illegal orphaning later in the\nstack. This change meant that the entire socket memory charge remained\nwith the head SKB, but the corresponding accounting logic in\nskb_segment_list() was never updated.\n\nAs a result, the current code unconditionally adds each fragment's\ntruesize to delta_truesize and subtracts it from the parent SKB. Since\nthe fragments are no longer charged to the socket, this subtraction\nresults in an effective under-count of memory when the head is freed.\nThis causes sk_wmem_alloc to remain non-zero, preventing socket\ndestruction and leading to a persistent memory leak.\n\nThe leak can be observed via KMEMLEAK when tearing down the networking\nenvironment:\n\nunreferenced object 0xffff8881e6eb9100 (size 2048):\n comm \"ping\", pid 6720, jiffies 4295492526\n backtrace:\n kmem_cache_alloc_noprof+0x5c6/0x800\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x35/0xa00\n inet6_create.part.0+0x303/0x10d0\n __sock_create+0x248/0x640\n __sys_socket+0x11b/0x1d0\n\nSince skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST\npackets constructed by GRO, the truesize adjustment is removed.\n\nThe call to skb_release_head_state() must be preserved. As documented in\ncommit cf673ed0e057 (\"net: fix fraglist segmentation reference count\nleak\"), it is still required to correctly drop references to SKB\nextensions that may be overwritten during __copy_skb_header()."
},
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"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: corrige fuga de memoria en skb_segment_list para paquetes GRO\n\nCuando se llama a skb_segment_list() durante el reenvío de paquetes, maneja paquetes que fueron agregados por el motor GRO.\n\nHistóricamente, la lógica de segmentación en skb_segment_list asume que los segmentos individuales se dividen de un SKB padre y pueden necesitar llevar su propia contabilidad de memoria de socket. En consecuencia, el código transfiere truesize del padre a los segmentos recién creados.\n\nAntes del commit ed4cccef64c1 ('gro: corrige transferencia de propiedad'), esta resta de truesize en skb_segment_list() era válida porque los fragmentos aún llevaban una referencia al socket original.\n\nSin embargo, el commit ed4cccef64c1 ('gro: corrige transferencia de propiedad') cambió este comportamiento al asegurar que las entradas de fraglist se huérfanan explícitamente (skb->sk = NULL) para evitar un huérfano ilegal más adelante en la pila. Este cambio significó que la carga completa de memoria del socket permaneció con el SKB de cabecera, pero la lógica de contabilidad correspondiente en skb_segment_list() nunca se actualizó.\n\nComo resultado, el código actual añade incondicionalmente el truesize de cada fragmento a delta_truesize y lo resta del SKB padre. Dado que los fragmentos ya no se cargan al socket, esta resta resulta en un recuento insuficiente efectivo de memoria cuando se libera la cabecera. Esto hace que sk_wmem_alloc permanezca distinto de cero, impidiendo la destrucción del socket y provocando una fuga de memoria persistente.\n\nLa fuga puede observarse a través de KMEMLEAK al desmantelar el entorno de red:\n\nobjeto sin referencia 0xffff8881e6eb9100 (tamaño 2048):\n comm \"ping\", pid 6720, jiffies 4295492526\n rastreo:\n kmem_cache_alloc_noprof+0x5c6/0x800\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x35/0xa00\n inet6_create.part.0+0x303/0x10d0\n __sock_create+0x248/0x640\n __sys_socket+0x11b/0x1d0\n\nDado que skb_segment_list() se utiliza exclusivamente para paquetes SKB_GSO_FRAGLIST construidos por GRO, el ajuste de truesize se elimina.\n\nLa llamada a skb_release_head_state() debe conservarse. Como se documenta en el commit cf673ed0e057 ('net: corrige fuga de recuento de referencias de segmentación de fraglist'), todavía es necesario para descartar correctamente las referencias a extensiones SKB que pueden ser sobrescritas durante __copy_skb_header()."
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"lastModified": "2026-07-14T13:18:21.023",
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