CVE-2026-74701

Estado: RecibidaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

net/openvswitch: check Ethernet header length in key_extract()

When a packet arrives on an ARPHRD_NONE device (e.g. TUN), ovs_flow_key_extract() trusts the user-provided skb->protocol field: if it is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and key_extract() is called without ensuring the skb has ETH_HLEN (14) bytes of linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes for MAC addresses and parse_ethertype() pulls 2 more, either of which triggers a kernel BUG in __skb_pull() when the linear area is too small.

Leer descripción completaMostrar menos

Fixed by calling check_header() in key_extract() before accessing the Ethernet header.

Detalles técnicos trazas, registros y código del informe original

  kernel BUG at include/linux/skbuff.h:2848!
  RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933
  ovs_flow_key_extract+0x419/0xa70
  ovs_vport_receive+0x222/0x390
  netdev_frame_hook+0x3e0/0x630
  tun_get_user+0x2d0c/0x38e0

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.13%
Percentil entre todas las CVEs puntuadas: 2
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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %

AV:L/PR:L sin UI:N permite escalar privilegios localmente explotando la falta de validación de longitud en el kernel. La vulnerabilidad causa BUG del kernel que genera denegación de servicio o potencialmente ejecución con privilegios elevados.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74701",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
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  "published": "2026-08-22T16:16:44.740",
  "references": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/openvswitch: check Ethernet header length in key_extract()\n\nWhen a packet arrives on an ARPHRD_NONE device (e.g. TUN),\novs_flow_key_extract() trusts the user-provided skb->protocol field: if\nit is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and\nkey_extract() is called without ensuring the skb has ETH_HLEN (14) bytes\nof linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes\nfor MAC addresses and parse_ethertype() pulls 2 more, either of which\ntriggers a kernel BUG in __skb_pull() when the linear area is too small.\n\n  kernel BUG at include/linux/skbuff.h:2848!\n  RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933\n  ovs_flow_key_extract+0x419/0xa70\n  ovs_vport_receive+0x222/0x390\n  netdev_frame_hook+0x3e0/0x630\n  tun_get_user+0x2d0c/0x38e0\n\nFixed by calling check_header() in key_extract() before accessing the\nEthernet header."
    }
  ],
  "lastModified": "2026-08-25T06:18:53.827",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}