CVE-2026-89564

Estado: RecibidaAlta (7.8)—

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

ip: orphan prefetched skbs before multicast forwarding

IPv4 and IPv6 input preserve an skb->sk association installed by bpf_sk_assign() so that local delivery can use the selected socket under RCU. Both address families can also prefetch a socket in UDP early demux. In both paths (BPF and UDP early demux) a reference is not guaranteed to be held on the socket.

When a multicast packet is not locally deliverable, IPv6 hands the original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the original skb when local delivery is not needed. Either path can put the skb on an unresolved multicast route queue or forward it after the receive-side RCU section ends.

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After the prefetched socket is destroyed, a later skb free invokes sock_pfree() and dereferences the stale skb->sk. Orphan the skb before each non-local multicast forwarding path. Local delivery retains the original skb; the existing skb_clone() calls provide multicast forwarding with a socket-free clone.

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: 0.14%
Percentil entre todas las CVEs puntuadas: 3
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 escalation60 %

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

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence Program 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-2026-89564",
  "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": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449",
              "lessThan": "e62aef7d6a5b27569bf540bbe11a9482117ff588",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449",
              "lessThan": "a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449",
              "lessThan": "f1281d4b99089fbaf0d3579bba62a814ebb4de4d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449",
              "lessThan": "e36ce6e78fe3fc3c071a26750783b7ba081ce10d",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/ipv4/ipmr.c",
            "net/ipv6/ip6_input.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.7",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/ipv4/ipmr.c",
            "net/ipv6/ip6_input.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:40.313",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e36ce6e78fe3fc3c071a26750783b7ba081ce10d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e62aef7d6a5b27569bf540bbe11a9482117ff588",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f1281d4b99089fbaf0d3579bba62a814ebb4de4d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip: orphan prefetched skbs before multicast forwarding\n\nIPv4 and IPv6 input preserve an skb->sk association installed by\nbpf_sk_assign() so that local delivery can use the selected socket under\nRCU. Both address families can also prefetch a socket in UDP early demux.\nIn both paths (BPF and UDP early demux) a reference is not guaranteed to\nbe held on the socket.\n\nWhen a multicast packet is not locally deliverable, IPv6 hands the\noriginal skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the\noriginal skb when local delivery is not needed. Either path can put the\nskb on an unresolved multicast route queue or forward it after the\nreceive-side RCU section ends.\n\nAfter the prefetched socket is destroyed, a later skb free invokes\nsock_pfree() and dereferences the stale skb->sk. Orphan the skb before\neach non-local multicast forwarding path. Local delivery retains the\noriginal skb; the existing skb_clone() calls provide multicast forwarding\nwith a socket-free clone."
    }
  ],
  "lastModified": "2026-09-21T14:17:23.440",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}