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CVE-2026-72421

Estado: RecibidaCrítica (10)—

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

ipv4: fib: Don't ignore error route in local/main tables.

When CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added, fib_lookup() performs route lookup directly on two tables.

Since the first lookup does not properly bail out, the result of an error route in the merged local/main table could be overwritten by another route in the default table:

Once a random rule is added, the error route is respected:

Let's fix the inconsistent behaviour.

Detalles técnicos trazas, registros y código del informe original
  # unshare -n
  # ip link set lo up
  # ip route add 192.168.0.0/24 dev lo table 253
  # ip route add unreachable 192.168.0.0/24
  # ip route get 192.168.0.1
  192.168.0.1 dev lo table default uid 0
      cache <local>

  # ip rule add table 0
  # ip rule del table 0
  # ip route get 192.168.0.1
  RTNETLINK answers: No route to host

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.

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

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficApplication 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)

Mostrar
{
  "id": "CVE-2026-72421",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 10,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.8,
        "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": "f4530fa574df4d833506c53697ed1daa0d390bf4",
              "lessThan": "a29e95fbc51e8a1b932773fd0e259b2080881443",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
              "lessThan": "5ae18d87a45698e8244d0fcba64c658c35a7dd3d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
              "lessThan": "9127589aabdee588278e8d0d0bd3709a760a92c8",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "49eaf1403201357762d745a35882fb734107d763",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
              "lessThan": "fd25996f57a95d56bc568c89b4921edcf334b7d8",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "828fad4fd418bcdb9f5d66fec0d184c52a85ec31",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "a668fa160247d7bbe921548cb845f607b8b9305f",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "b72f0db64205d9ce462038ba995d5d31eff32dc1",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "include/net/ip_fib.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.6"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.6",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "include/net/ip_fib.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:15.867",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/49eaf1403201357762d745a35882fb734107d763",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5ae18d87a45698e8244d0fcba64c658c35a7dd3d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/828fad4fd418bcdb9f5d66fec0d184c52a85ec31",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9127589aabdee588278e8d0d0bd3709a760a92c8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a29e95fbc51e8a1b932773fd0e259b2080881443",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a668fa160247d7bbe921548cb845f607b8b9305f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b72f0db64205d9ce462038ba995d5d31eff32dc1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fd25996f57a95d56bc568c89b4921edcf334b7d8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: fib: Don't ignore error route in local/main tables.\n\nWhen CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added,\nfib_lookup() performs route lookup directly on two tables.\n\nSince the first lookup does not properly bail out, the result\nof an error route in the merged local/main table could be\noverwritten by another route in the default table:\n\n  # unshare -n\n  # ip link set lo up\n  # ip route add 192.168.0.0/24 dev lo table 253\n  # ip route add unreachable 192.168.0.0/24\n  # ip route get 192.168.0.1\n  192.168.0.1 dev lo table default uid 0\n      cache <local>\n\nOnce a random rule is added, the error route is respected:\n\n  # ip rule add table 0\n  # ip rule del table 0\n  # ip route get 192.168.0.1\n  RTNETLINK answers: No route to host\n\nLet's fix the inconsistent behaviour."
    }
  ],
  "lastModified": "2026-08-17T06:19:09.257",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}