CVE-2026-64554

Estado: RecibidaAlta (8.8)—

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

netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()

br_ip6_fragment() gets prevhdr, a pointer into the skb head, from ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb skb_checksum_help() reallocates the head via pskb_expand_head(), leaving prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a use-after-free write.

Save prevhdr's offset before skb_checksum_help() and recompute it after, like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6 fragment").

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)
  Write of size 1 at addr ffff888013ff5016 by task exploit/141
  Call Trace:
   ...
   kasan_report (mm/kasan/report.c:595)
   ip6_frag_next (net/ipv6/ip6_output.c:857)
   br_ip6_fragment (net/ipv6/netfilter.c:212)
   nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)
   nf_hook_slow (net/netfilter/core.c:619)
   br_forward_finish (net/bridge/br_forward.c:66)
   __br_forward (net/bridge/br_forward.c:115)
   maybe_deliver (net/bridge/br_forward.c:191)
   br_flood (net/bridge/br_forward.c:245)
   br_handle_frame_finish (net/bridge/br_input.c:229)
   br_handle_frame (net/bridge/br_input.c:442)
   ...
   packet_sendmsg (net/packet/af_packet.c:3114)
   ...
   do_syscall_64 (arch/x86/entry/syscall_64.c:94)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
  Kernel panic - not syncing: Fatal exception in interrupt

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 8.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.26%
Percentil entre todas las CVEs puntuadas: 16
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.

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement75 %
Impacto principalT1499.004 Application or System Exploitationimpact65 %
Impacto secundarioT1068 Exploitation for Privilege Escalationprivilege escalation60 %

AV:A (red adyacente) sin privilegios previos → T1210. Kernel panic y KASAN use-after-free indican DoS (T1499.004) e inestabilidad de privilegios (T1068) en bridge Linux.

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 Program Application Isolation and Sandboxing Exploit Protection Update Software Vulnerability Scanning Privileged Account Management

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-2026-64554",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "ADJACENT_NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:A/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"
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        "impactScore": 5.9,
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              "version": "6.1.178",
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            },
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              "version": "6.6.145",
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          ],
          "programFiles": [
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    }
  ],
  "published": "2026-07-27T21:17:08.437",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/00c06ef8c018493943891a7d0ca82b71b24f3180",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()\n\nbr_ip6_fragment() gets prevhdr, a pointer into the skb head, from\nip6_find_1stfragopt(), then calls skb_checksum_help().  For a cloned skb\nskb_checksum_help() reallocates the head via pskb_expand_head(), leaving\nprevhdr dangling.  It is later dereferenced in ip6_frag_next(), causing a\nuse-after-free write.\n\nSave prevhdr's offset before skb_checksum_help() and recompute it after,\nlike commit ef0efcd3bd3f (\"ipv6: Fix dangling pointer when ipv6\nfragment\").\n\n  BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)\n  Write of size 1 at addr ffff888013ff5016 by task exploit/141\n  Call Trace:\n   ...\n   kasan_report (mm/kasan/report.c:595)\n   ip6_frag_next (net/ipv6/ip6_output.c:857)\n   br_ip6_fragment (net/ipv6/netfilter.c:212)\n   nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)\n   nf_hook_slow (net/netfilter/core.c:619)\n   br_forward_finish (net/bridge/br_forward.c:66)\n   __br_forward (net/bridge/br_forward.c:115)\n   maybe_deliver (net/bridge/br_forward.c:191)\n   br_flood (net/bridge/br_forward.c:245)\n   br_handle_frame_finish (net/bridge/br_input.c:229)\n   br_handle_frame (net/bridge/br_input.c:442)\n   ...\n   packet_sendmsg (net/packet/af_packet.c:3114)\n   ...\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n  Kernel panic - not syncing: Fatal exception in interrupt"
    }
  ],
  "lastModified": "2026-08-17T05:18:00.960",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}