CVE-2026-80995

Estado: RecibidaAlta (7.8)—

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

net: mctp: hold a reference to the route device in mctp_route_lookup()

mctp_route_lookup() uses rt->dev without holding a reference on it. mctp_route_lookup_single() returns the route under RCU only, so the route's device can be torn down concurrently: mctp_dev_put() drops the last reference and synchronously kfree()s mdev->addrs. mctp_dev_saddr() then reads rt->dev->addrs[0], giving a use-after-free reachable by an unprivileged local AF_MCTP user on the receive/forwarding path (no CAP_NET_RAW required):

In the same window mctp_dst_from_route() -> mctp_dev_hold() also increments a refcount that has already reached zero ("refcount_t: addition on 0 ... mctp_dev_hold").

Leer descripción completaMostrar menos

This reintroduces the use-after-free class of CVE-2023-3439: the source address lookup was moved ahead of the point where the destination takes its device reference.

Take a reference with refcount_inc_not_zero() before touching rt->dev, skip a device that is already dead, and drop the reference once the destination has taken its own.

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-use-after-free in mctp_route_lookup
  Read of size 1 at addr ... by task mctp_uaf/...
   mctp_route_lookup
   mctp_pkttype_receive
  Freed by task ...:
   kfree
   mctp_dev_put
   mctp_dev_notify

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: 0.17%
Percentil entre todas las CVEs puntuadas: 5
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 escalation85 %
Impacto principalT1005 Data from Local Systemcollection75 %
Impacto secundarioT1499.004 Application or System Exploitationimpact65 %

Vulnerabilidad de use-after-free en kernel Linux (AV:L, PR:L, UI:N) explotable por usuario local sin CAP_NET_RAW. Impacto: lectura de memoria (mdev->addrs) y potencial DoS por corrupción de estado.

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)

Mostrar

{
  "id": "CVE-2026-80995",
  "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": "22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1",
              "lessThan": "cc561f8af25586300c2f9d285babb163b866b293",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1",
              "lessThan": "408da1df18116c971c3392e21e50586688cd3fbf",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/mctp/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": "7.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.1",
              "versionType": "semver"
            },
            {
              "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/mctp/route.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:06.497",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/408da1df18116c971c3392e21e50586688cd3fbf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cc561f8af25586300c2f9d285babb163b866b293",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: hold a reference to the route device in mctp_route_lookup()\n\nmctp_route_lookup() uses rt->dev without holding a reference on it.\nmctp_route_lookup_single() returns the route under RCU only, so the\nroute's device can be torn down concurrently: mctp_dev_put() drops the\nlast reference and synchronously kfree()s mdev->addrs.  mctp_dev_saddr()\nthen reads rt->dev->addrs[0], giving a use-after-free reachable by an\nunprivileged local AF_MCTP user on the receive/forwarding path (no\nCAP_NET_RAW required):\n\n  BUG: KASAN: slab-use-after-free in mctp_route_lookup\n  Read of size 1 at addr ... by task mctp_uaf/...\n   mctp_route_lookup\n   mctp_pkttype_receive\n  Freed by task ...:\n   kfree\n   mctp_dev_put\n   mctp_dev_notify\n\nIn the same window mctp_dst_from_route() -> mctp_dev_hold() also\nincrements a refcount that has already reached zero\n(\"refcount_t: addition on 0 ... mctp_dev_hold\").\n\nThis reintroduces the use-after-free class of CVE-2023-3439: the source\naddress lookup was moved ahead of the point where the destination takes\nits device reference.\n\nTake a reference with refcount_inc_not_zero() before touching rt->dev,\nskip a device that is already dead, and drop the reference once the\ndestination has taken its own."
    }
  ],
  "lastModified": "2026-09-13T07:17:06.230",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}