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CVE-2026-74743

Estado: RecibidaCrítica (9.8)—

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

macvlan: inherit needed_headroom and needed_tailroom from lowerdev

macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0.

When the underlying lowerdev requires extra headroom or tailroom for headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx headroom), upper layers calculating packet headroom and tailroom fail to reserve sufficient space.

This can result in reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes when dev_hard_header() / macvlan_hard_header() prepends header data or when lower devices append tailroom.

Leer descripción completaMostrar menos

Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.

CVSS

Probabilidad de explotación (EPSS)

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.

Vulnerabilidad remota en el kernel Linux (AV:N, PR:N, UI:N) que causa DoS por corrupción de memoria (slab-use-after-free) al no reservar espacio suficiente en paquetes de red, permitiendo ataques de denegación de servicio e integridad de datos.

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (1)

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

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74743",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
              "lessThan": "c2ef3f134b069c54b9cc95cce1a16c38c4939336",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
              "lessThan": "7b0eb3e0f363ca79a3af9efd2e87c6258f11da2b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
              "lessThan": "8cd90e850e434577bf6774778657d26d6995e53f",
              "versionType": "git"
            },
            {
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              "lessThan": "28afc87bd8da0b3348bbbd834c8a89e83712cf5e",
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            {
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              "lessThan": "8f6a05dbac05725e0786701eb04778c5bdbe4eaa",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
              "lessThan": "96fa90b74385b7f2b0d97251dd43d5ee6ca44668",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "cef51860becd9700217c81732ca1eb1ea6ed6fe1",
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          ],
          "programFiles": [
            "drivers/net/macvlan.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.23"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.23",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.153",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/net/macvlan.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-26T15:16:53.113",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/28afc87bd8da0b3348bbbd834c8a89e83712cf5e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7b0eb3e0f363ca79a3af9efd2e87c6258f11da2b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8cd90e850e434577bf6774778657d26d6995e53f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8f6a05dbac05725e0786701eb04778c5bdbe4eaa",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/96fa90b74385b7f2b0d97251dd43d5ee6ca44668",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c2ef3f134b069c54b9cc95cce1a16c38c4939336",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cef51860becd9700217c81732ca1eb1ea6ed6fe1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: inherit needed_headroom and needed_tailroom from lowerdev\n\nmacvlan devices inherit hard_header_len from lowerdev during macvlan_init(),\nbut leave needed_headroom and needed_tailroom set to 0.\n\nWhen the underlying lowerdev requires extra headroom or tailroom for\nheaders/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx\nheadroom), upper layers calculating packet headroom and tailroom fail to\nreserve sufficient space.\n\nThis can result in reallocation overhead, skb headroom underflows, or KASAN\nslab-use-after-free crashes when dev_hard_header() / macvlan_hard_header()\nprepends header data or when lower devices append tailroom.\n\nFix this by:\n1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init().\n2. Propagating needed_headroom and needed_tailroom updates to attached macvlans\n   in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events."
    }
  ],
  "lastModified": "2026-10-03T11:17:39.257",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}