CVE-2026-74598

Estado: RecibidaAlta (7.5)—

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

ipv6: fix Route Information option length validation

rt6_route_rcv() validates the Route Information option (RFC 4191) length against the prefix length, but both checks are off by one.

rinfo->length is the ND option length in units of 8 octets and it *includes* the 8-byte option header, so an option carrying N bytes of prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3 when Prefix Length is greater than 64, and 2 or 3 when it is greater than 0. The code accepts length >= 2 and length >= 1 respectively.

ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix, so a Router Advertisement with (prefix_len=128, length=2) or (prefix_len=64, length=1) makes the kernel read up to 8 bytes past the end of the option.

Leer descripción completaMostrar menos

Those bytes end up in the prefix of the route that gets installed, so they are visible to userspace:

When the Route Information option is the last one in the packet, those eight bytes come from the skb tail room instead.

Reject the option lengths RFC 4191 does not allow.

Detalles técnicos trazas, registros y código del informe original

  # RA with a Route Information option (prefix_len=128, length=2)
  # followed by a source link-layer address option, 01 01 de ad be ef ca fe
  $ ip -6 route show
  2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra
                     ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.43%
Percentil entre todas las CVEs puntuadas: 35
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application 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 Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-74598",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "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": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "2f6f94eda12430fb41b24b44a71e2ea4e93561d7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "7eac87396c44a312be457ef41d4c5687883be9a2",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "7309529f257ae18e72112ef9f614edfd6df229bb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "ff3cb05289b8a4ef95fa7ea14c7d34818359edbb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "3b2231e358d26e3aec5d8040b1fb777af03c5f05",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "da64ed1f346ba84df574d6469fa2e422b2511719",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "70ceb4f53929f73746be72f73707cd9f8753e2fc",
              "lessThan": "d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.17"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.17",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-22T16:16:32.170",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2f6f94eda12430fb41b24b44a71e2ea4e93561d7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3b2231e358d26e3aec5d8040b1fb777af03c5f05",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7309529f257ae18e72112ef9f614edfd6df229bb",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7eac87396c44a312be457ef41d4c5687883be9a2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/da64ed1f346ba84df574d6469fa2e422b2511719",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ff3cb05289b8a4ef95fa7ea14c7d34818359edbb",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix Route Information option length validation\n\nrt6_route_rcv() validates the Route Information option (RFC 4191) length\nagainst the prefix length, but both checks are off by one.\n\nrinfo->length is the ND option length in units of 8 octets and it\n*includes* the 8-byte option header, so an option carrying N bytes of\nprefix has length == 1 + N/8.  RFC 4191 section 2.3 requires length 3\nwhen Prefix Length is greater than 64, and 2 or 3 when it is greater\nthan 0.  The code accepts length >= 2 and length >= 1 respectively.\n\nipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix,\nso a Router Advertisement with (prefix_len=128, length=2) or\n(prefix_len=64, length=1) makes the kernel read up to 8 bytes past the\nend of the option.  Those bytes end up in the prefix of the route that\ngets installed, so they are visible to userspace:\n\n  # RA with a Route Information option (prefix_len=128, length=2)\n  # followed by a source link-layer address option, 01 01 de ad be ef ca fe\n  $ ip -6 route show\n  2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra\n                     ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds\n\nWhen the Route Information option is the last one in the packet, those\neight bytes come from the skb tail room instead.\n\nReject the option lengths RFC 4191 does not allow."
    }
  ],
  "lastModified": "2026-08-25T06:18:35.740",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}