CVE-2025-68775

Estado: AplazadaCrítica (9.8)—

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

net/handshake: duplicate handshake cancellations leak socket

When a handshake request is cancelled it is removed from the handshake_net->hn_requests list, but it is still present in the handshake_rhashtbl until it is destroyed.

If a second cancellation request arrives for the same handshake request, then remove_pending() will return false... and assuming HANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue processing through the out_true label, where we put another reference on the sock and a refcount underflow occurs.

Leer descripción completaMostrar menos

This can happen for example if a handshake times out - particularly if the SUNRPC client sends the AUTH_TLS probe to the server but doesn't follow it up with the ClientHello due to a problem with tlshd. When the timeout is hit on the server, the server will send a FIN, which triggers a cancellation request via xs_reset_transport(). When the timeout is hit on the client, another cancellation request happens via xs_tls_handshake_sync().

Add a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel path so duplicate cancels can be detected.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.53%
Percentil entre todas las CVEs puntuadas: 43
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %
Impacto principalT1499.004 Application or System Exploitationimpact65 %
Impacto secundarioT1068 Exploitation for Privilege Escalationprivilege escalation70 %

Vulnerabilidad en kernel Linux (red sin privilegios, AV:N/PR:N) que permite DoS por agotamiento de memoria (refcount underflow) y potencial escalada de privilegios local mediante 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

Filter Network Traffic Application Isolation and Sandboxing Exploit Protection Update Software Vulnerability Scanning Threat Intelligence Program

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-2025-68775",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/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"
        },
        "impactScore": 5.9,
        "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": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "lessThan": "011ae80c49d9bfa5b4336f8bd387cd25c7593663",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "lessThan": "e1641177e7fb48a0a5a06658d4aab51da6656659",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "lessThan": "3c330f1dee3cd92b57e19b9d21dc8ce5970b09be",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "lessThan": "15564bd67e2975002f2a8e9defee33e321d3183f",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/handshake/request.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.4",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.120",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/handshake/request.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-01-13T16:15:57.073",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: duplicate handshake cancellations leak socket\n\nWhen a handshake request is cancelled it is removed from the\nhandshake_net->hn_requests list, but it is still present in the\nhandshake_rhashtbl until it is destroyed.\n\nIf a second cancellation request arrives for the same handshake request,\nthen remove_pending() will return false... and assuming\nHANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue\nprocessing through the out_true label, where we put another reference on\nthe sock and a refcount underflow occurs.\n\nThis can happen for example if a handshake times out - particularly if\nthe SUNRPC client sends the AUTH_TLS probe to the server but doesn't\nfollow it up with the ClientHello due to a problem with tlshd.  When the\ntimeout is hit on the server, the server will send a FIN, which triggers\na cancellation request via xs_reset_transport().  When the timeout is\nhit on the client, another cancellation request happens via\nxs_tls_handshake_sync().\n\nAdd a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel\npath so duplicate cancels can be detected."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/handshake: las cancelaciones duplicadas de handshake fugan el socket\n\nCuando una solicitud de handshake es cancelada, es eliminada de la lista handshake_net-&gt;hn_requests, pero aún está presente en la handshake_rhashtbl hasta que es destruida.\n\nSi llega una segunda solicitud de cancelación para la misma solicitud de handshake, entonces remove_pending() devolverá falso... y asumiendo que HANDSHAKE_F_REQ_COMPLETED no está establecido en req-&gt;hr_flags, continuaremos procesando a través de la etiqueta out_true, donde ponemos otra referencia en el sock y ocurre un desbordamiento negativo del contador de referencias.\n\nEsto puede ocurrir por ejemplo si un handshake agota el tiempo de espera, particularmente si el cliente SUNRPC envía la sonda AUTH_TLS al servidor pero no la sigue con el ClientHello debido a un problema con tlshd. Cuando se alcanza el tiempo de espera en el servidor, el servidor enviará un FIN, lo que activa una solicitud de cancelación a través de xs_reset_transport(). Cuando se alcanza el tiempo de espera en el cliente, ocurre otra solicitud de cancelación a través de xs_tls_handshake_sync().\n\nAñadir un test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) en la ruta de cancelación pendiente para que las cancelaciones duplicadas puedan ser detectadas."
    }
  ],
  "lastModified": "2026-07-30T06:24:43.687",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}