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CVE-2026-64009

Estado: Pendiente de análisisAlta (7.8)—

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

xfrm: Check for underflow in xfrm_state_mtu

Leo Lin reported OOB write issue in esp component:

Check for underflow and return 1. This causes the sendmsg attempt to fail with ENETUNREACH.

Detalles técnicos trazas, registros y código del informe original
  xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned
  modulo-2^32 space using an attacker-influenced "header_len + authsize +
  net_adj" subtracted from a small "mtu" argument. A nobody user can
  install an IPv4 ESP tunnel SA with a large authentication key
  (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc),
  configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a
  large value. When a single UDP datagram is then sent through the
  tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and
  esp_output() consumes it as a signed int via:

        padto      = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached))
        esp.tfclen = padto - skb->len   (assigned to int)

  esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t
  when passed to memset() inside esp_output_fill_trailer(), producing a
  ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as
  "Write of size 18446744073709551537 at addr ffff888...".

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 local con AV:L/PR:L que permite a un usuario con privilegios bajos causar OOB write y DoS mediante configuración maliciosa de parámetros ESP (tfcpad, MTU, authsize); subdesbordamiento en xfrm_state_mtu genera escritura masiva de memoria.

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 ProgramRestrict File and Directory PermissionsRemote Data StorageFilter Network TrafficExecution PreventionEncrypt Sensitive Information

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)

Mostrar
{
  "id": "CVE-2026-64009",
  "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",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "c5c2523893747f88a83376abad310c8ad13f7197",
              "lessThan": "8014f70c4e6e5ab101ae3860a614e65e988372e3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c5c2523893747f88a83376abad310c8ad13f7197",
              "lessThan": "1021d2877b689a648b27815c854557a917122e93",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "2a41b1b31c61c52b972278ce1732a1443f5e89ed",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "fccd685b32df5aaf6bad4381eeda216468e283f0",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "820e501be8aee4b365d218d83227b314309c5fda",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "82ac903e0b519849647657b8c48d21237ada06a2",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "versionType": "git"
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            {
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              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.22"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.22",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/xfrm/xfrm_state.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-19T16:17:40.663",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1021d2877b689a648b27815c854557a917122e93",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2a41b1b31c61c52b972278ce1732a1443f5e89ed",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3db50ceeacb52806d8fe86fb1dfe944df0b9f789",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/742b04d0550b0ec89dcbc99537ec88653bd1ad90",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8014f70c4e6e5ab101ae3860a614e65e988372e3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/820e501be8aee4b365d218d83227b314309c5fda",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/82ac903e0b519849647657b8c48d21237ada06a2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fccd685b32df5aaf6bad4381eeda216468e283f0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Check for underflow in xfrm_state_mtu\n\nLeo Lin reported OOB write issue in esp component:\n\n  xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned\n  modulo-2^32 space using an attacker-influenced \"header_len + authsize +\n  net_adj\" subtracted from a small \"mtu\" argument. A nobody user can\n  install an IPv4 ESP tunnel SA with a large authentication key\n  (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc),\n  configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a\n  large value. When a single UDP datagram is then sent through the\n  tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and\n  esp_output() consumes it as a signed int via:\n\n        padto      = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached))\n        esp.tfclen = padto - skb->len   (assigned to int)\n\n  esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t\n  when passed to memset() inside esp_output_fill_trailer(), producing a\n  ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as\n  \"Write of size 18446744073709551537 at addr ffff888...\".\n\nCheck for underflow and return 1. This causes the sendmsg attempt to\nfail with ENETUNREACH."
    }
  ],
  "lastModified": "2026-07-30T14:59:47.950",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}