CVE-2026-46321
In the Linux kernel, the following vulnerability has been resolved:
tun: free page on short-frame rejection in tun_xdp_one()
tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without freeing the page that vhost_net_build_xdp() allocated for it. tun_sendmsg() discards that -EINVAL and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page; each short frame in a batch leaks one page-frag chunk.
A local process that can open /dev/net/tun and /dev/vhost-net can hit this path: it attaches a tun/tap device as the vhost-net backend and feeds TX descriptors whose length minus the virtio-net header is below ETH_HLEN.
Leer descripción completaMostrar menos
Each kick leaks the page-frag chunks for that batch, and a tight submission loop exhausts host memory and triggers an OOM panic. Free the page before returning -EINVAL, matching the XDP-program error path in the same function.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- Puntuación base: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.19%
- Percentil entre todas las CVEs puntuadas: 7
- Fecha de la puntuación: 4/10/2026
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).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1499.004Application or System Exploitationimpact80 % - Impacto secundario
T1578.003Delete Cloud Instancedefense impairment70 %
Acceso local sin autenticación (AV:L, PR:N) permite exhaust memoria vía /dev/net/tun; genera DoS por agotamiento de recursos (A:H) y potencial destrucción de instancias.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/0a6f46a9332ad6958992d64d3b3a81a80b2ca940
- https://git.kernel.org/stable/c/0e8211fcf9426f5adddf32516ba0f400ceb9544d
- https://git.kernel.org/stable/c/37a1c268c2c8090bf4dc552d732bd23ba36f8eb0
- https://git.kernel.org/stable/c/5b34f9e4fe2f203724a6e893d6df0316b9670057
- https://git.kernel.org/stable/c/69863ff2720a0e9871f1a5710f2a33a94217fee0
- https://git.kernel.org/stable/c/98c67be9eb9de72465a071949e84a3cdb8fab5a3
- https://git.kernel.org/stable/c/e915445942af6dcea628bf66d6241641201a0c41
- https://git.kernel.org/stable/c/f4feb1e20058e407cb00f45aff47f5b7e19a6bbf
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntun: free page on short-frame rejection in tun_xdp_one()\n\ntun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without\nfreeing the page that vhost_net_build_xdp() allocated for it.\ntun_sendmsg() discards that -EINVAL and still returns total_len, so\nvhost_tx_batch() takes the success path and never frees the page; each\nshort frame in a batch leaks one page-frag chunk.\n\nA local process that can open /dev/net/tun and /dev/vhost-net can hit\nthis path: it attaches a tun/tap device as the vhost-net backend and\nfeeds TX descriptors whose length minus the virtio-net header is below\nETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a\ntight submission loop exhausts host memory and triggers an OOM panic.\nFree the page before returning -EINVAL, matching the XDP-program error\npath in the same function."
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"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ntun: liberar página en el rechazo de tramas cortas en tun_xdp_one()\n\ntun_xdp_one() devuelve -EINVAL en una trama más corta que ETH_HLEN sin liberar la página que vhost_net_build_xdp() asignó para ella. tun_sendmsg() descarta ese -EINVAL y aún devuelve total_len, por lo que vhost_tx_batch() toma la ruta de éxito y nunca libera la página; cada trama corta en un lote filtra un chunk de fragmento de página.\n\nUn proceso local que puede abrir /dev/net/tun y /dev/vhost-net puede alcanzar esta ruta: adjunta un dispositivo tun/tap como el backend de vhost-net y alimenta descriptores TX cuya longitud menos el encabezado virtio-net está por debajo de ETH_HLEN. Cada kick filtra los chunks de fragmentos de página para ese lote, y un bucle de envío ajustado agota la memoria del host y desencadena un pánico OOM. Liberar la página antes de devolver -EINVAL, coincidiendo con la ruta de error del programa XDP en la misma función."
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