CVE-2026-46132
Estado: En análisisMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo
rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack without initialisation:
The struct contains a single fixed 32-byte field:
The function then copies dev->broadcast into it using dev->addr_len as the length:
On Ethernet devices (the overwhelming majority of SR-IOV NICs) dev->addr_len is 6, so only the first 6 bytes of broadcast[] are written. The remaining 26 bytes retain whatever was previously on the kernel stack. The full struct is then handed to userspace via:
Leer descripción completaMostrar menos
leaking up to 26 bytes of uninitialised kernel stack per VF per RTM_GETLINK request, repeatable.
The other vf_* structs in the same function are explicitly zeroed for exactly this reason - see the memset() calls for ivi, vf_vlan_info, node_guid and port_guid a few lines above. vf_broadcast was simply missed when it was added.
Reachability: any unprivileged local process can open AF_NETLINK / NETLINK_ROUTE without capabilities and send RTM_GETLINK with an IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per VF per request. Stack residue at this call site can include return addresses and transient sensitive data; KASAN with stack instrumentation, or KMSAN, will flag the nla_put() when reproduced.
Zero the on-stack struct before the partial memcpy, matching the existing pattern used for the other vf_* structs in the same function.
Detalles técnicos trazas, registros y código del informe original
struct ifla_vf_broadcast vf_broadcast;
/* include/uapi/linux/if_link.h */
struct ifla_vf_broadcast {
__u8 broadcast[32];
};
memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);
nla_put(skb, IFLA_VF_BROADCAST,
sizeof(vf_broadcast), &vf_broadcast)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: 0.17%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 5/10/2026
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-908
Referencias
- https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00
- https://git.kernel.org/stable/c/14271b401ec6a4bf0d88054106fc2956084717e1
- https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011
- https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0
- https://git.kernel.org/stable/c/a44fbb631cba646532f3948636626f81717365a7
- https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8
- https://git.kernel.org/stable/c/cccce3190ba4356432b9f22369b56123d3d89f0d
- https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5
- 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: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo\n\nrtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack\nwithout initialisation:\n\n\tstruct ifla_vf_broadcast vf_broadcast;\n\nThe struct contains a single fixed 32-byte field:\n\n\t/* include/uapi/linux/if_link.h */\n\tstruct ifla_vf_broadcast {\n\t\t__u8 broadcast[32];\n\t};\n\nThe function then copies dev->broadcast into it using dev->addr_len\nas the length:\n\n\tmemcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);\n\nOn Ethernet devices (the overwhelming majority of SR-IOV NICs)\ndev->addr_len is 6, so only the first 6 bytes of broadcast[] are\nwritten. The remaining 26 bytes retain whatever was previously on\nthe kernel stack. The full struct is then handed to userspace via:\n\n\tnla_put(skb, IFLA_VF_BROADCAST,\n\t\tsizeof(vf_broadcast), &vf_broadcast)\n\nleaking up to 26 bytes of uninitialised kernel stack per VF per\nRTM_GETLINK request, repeatable.\n\nThe other vf_* structs in the same function are explicitly zeroed\nfor exactly this reason - see the memset() calls for ivi,\nvf_vlan_info, node_guid and port_guid a few lines above.\nvf_broadcast was simply missed when it was added.\n\nReachability: any unprivileged local process can open AF_NETLINK /\nNETLINK_ROUTE without capabilities and send RTM_GETLINK with an\nIFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks\neach VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per\nVF per request. Stack residue at this call site can include return\naddresses and transient sensitive data; KASAN with stack\ninstrumentation, or KMSAN, will flag the nla_put() when reproduced.\n\nZero the on-stack struct before the partial memcpy, matching the\nexisting pattern used for the other vf_* structs in the same\nfunction."
}
],
"lastModified": "2026-09-08T09:18:08.247",
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