CVE-2026-72255

Estado: RecibidaAlta (7.8)—

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

netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst

The br_netfilter fake rtable is embedded in struct net_bridge and is attached to bridged packets with skb_dst_set_noref(). If such a packet is queued to NFQUEUE, __nf_queue() upgrades that fake dst with skb_dst_force().

At that point the queued skb can hold a real dst reference after bridge teardown has started. The problem is not that every bridged packet needs its own dst reference. The problem is that NFQUEUE can keep the bridge private fake dst alive after unregister begins.

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Fix this by keeping the bridge fake dst model unchanged and pinning the bridge master device only while the packet sits in NFQUEUE. Record the bridge device in nf_queue_entry when the queued skb carries a bridge fake dst, take a device reference for the queue lifetime, and drop it when the queue entry is freed.

Also make sure queued entries are reaped when that bridge device goes down, and drop the redundant nf_bridge_info_exists() test from the fake dst detection.

This keeps netdev_priv(br->dev) alive until verdict completion, so the embedded fake rtable and its metrics backing storage cannot be freed out from under dst_release(). It also avoids the constant refcount bump and avoids using ipv4-specific dst helpers for IPv6 bridge traffic.

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: 0.18%
Percentil entre todas las CVEs puntuadas: 7
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto secundarioT1499 Endpoint Denial of Serviceimpact65 %

Vulnerabilidad local (AV:L/PR:L) en el kernel Linux que permite a un atacante local causar condiciones de use-after-free mediante NFQUEUE, resultando en negación de servicio o corrupción 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 Program Filter Network Traffic 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-2026-72255",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
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          "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",
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  "published": "2026-08-15T06:21:53.127",
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    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst\n\nThe br_netfilter fake rtable is embedded in struct net_bridge and is\nattached to bridged packets with skb_dst_set_noref(). If such a packet is\nqueued to NFQUEUE, __nf_queue() upgrades that fake dst with\nskb_dst_force().\n\nAt that point the queued skb can hold a real dst reference after bridge\nteardown has started. The problem is not that every bridged packet needs\nits own dst reference. The problem is that NFQUEUE can keep the bridge\nprivate fake dst alive after unregister begins.\n\nFix this by keeping the bridge fake dst model unchanged and pinning the\nbridge master device only while the packet sits in NFQUEUE. Record the\nbridge device in nf_queue_entry when the queued skb carries a bridge fake\ndst, take a device reference for the queue lifetime, and drop it when the\nqueue entry is freed.\n\nAlso make sure queued entries are reaped when that bridge device goes\ndown, and drop the redundant nf_bridge_info_exists() test from the fake\ndst detection.\n\nThis keeps netdev_priv(br->dev) alive until verdict completion, so the\nembedded fake rtable and its metrics backing storage cannot be freed out\nfrom under dst_release(). It also avoids the constant refcount bump and\navoids using ipv4-specific dst helpers for IPv6 bridge traffic."
    }
  ],
  "lastModified": "2026-09-14T12:17:44.953",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}