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CVE-2026-93224

Estado: RecibidaAlta (8.1)—

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

svcrdma: Fix unmatched rn_unregister on failed accept

When svc_rdma_accept() takes the errout path before rpcrdma_rn_register() has succeeded, the existing cleanup block calls rpcrdma_rn_unregister(dev, &newxprt->sc_rn) unconditionally. svcxprt_rdma is kzalloc'd, so on that path sc_rn.rn_index is 0 and sc_rn.rn_done is NULL; the unregister therefore xa_erase()s another caller's slot 0 and performs an unmatched kref_put() on the rpcrdma_device's rd_kref.

The same errout also brackets the cleanup with svc_xprt_get()/ svc_xprt_put() around the kref_init() birth reference. The kref goes 1 -> 2 -> 1 and never reaches 0, so the svcxprt_rdma (and the net/ns_tracker it pinned) is leaked on every failed accept.

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rpcrdma_rn_register() writes rn->rn_done last, only after xa_alloc() and kref_get() have both succeeded, so rn_done == NULL is a natural "never registered" sentinel. Guard rpcrdma_rn_unregister() with an early return when rn_done is NULL, and clear rn_done before the matching xa_erase() so a repeated unregister is also a no-op.

With that guard in place, the accept errout drops the kref_init() birth reference via svc_xprt_put(), which dispatches svc_rdma_free(). Teardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing IS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new rn_done sentinel; sc_cm_id is non-NULL on every errout path because svc_rdma_accept() dereferences it above the first goto errout.

svc_xprt_free() drops the module reference associated with the freed transport, and svc_handle_xprt() drops its pre-acquired reference when ->xpo_accept() returns NULL. Take a replacement module reference before svc_xprt_put() so the two module_put()s remain balanced.

The rn_done guard also covers svc_rdma_free()'s non-listener call to rpcrdma_rn_unregister() for transports whose register attempt failed or never ran.

CVSS

Probabilidad de explotación (EPSS)

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.

Vulnerabilidad en kernel RDMA con vector AV:N que permite DoS por fallos en manejo de memoria (kref y xa_erase desapareados) y corrupción de estado; acceso remoto sin privilegios pero AC:H limita confianza.

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

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-93224",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.1,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 2.2
      }
    ]
  },
  "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": "cb3cba0ec372fa7c5f5f5c12990bef02e458ab86",
              "lessThan": "0335800071a6dfdf7d21d729b5e7d8fa98936211",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932",
              "lessThan": "5aabe070c00e5bdf4ab150fb5f72ad5f266d6241",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932",
              "lessThan": "45a444a17240f4fa2235f0dfd4a96fc80f1eb2c2",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932",
              "lessThan": "26190394c64c9429481fc88a4738f70bb92fb352",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d310955106c358c8e1ea682defd8e21af44a6cba",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.12.35",
              "lessThan": "6.12.109",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.15.4",
              "lessThan": "6.16",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "net/sunrpc/xprtrdma/ib_client.c",
            "net/sunrpc/xprtrdma/svc_rdma_transport.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.109",
              "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/sunrpc/xprtrdma/ib_client.c",
            "net/sunrpc/xprtrdma/svc_rdma_transport.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-24T16:17:17.720",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0335800071a6dfdf7d21d729b5e7d8fa98936211",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/26190394c64c9429481fc88a4738f70bb92fb352",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/45a444a17240f4fa2235f0dfd4a96fc80f1eb2c2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5aabe070c00e5bdf4ab150fb5f72ad5f266d6241",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix unmatched rn_unregister on failed accept\n\nWhen svc_rdma_accept() takes the errout path before\nrpcrdma_rn_register() has succeeded, the existing cleanup block\ncalls rpcrdma_rn_unregister(dev, &newxprt->sc_rn) unconditionally.\nsvcxprt_rdma is kzalloc'd, so on that path sc_rn.rn_index is 0 and\nsc_rn.rn_done is NULL; the unregister therefore xa_erase()s another\ncaller's slot 0 and performs an unmatched kref_put() on the\nrpcrdma_device's rd_kref.\n\nThe same errout also brackets the cleanup with svc_xprt_get()/\nsvc_xprt_put() around the kref_init() birth reference. The kref\ngoes 1 -> 2 -> 1 and never reaches 0, so the svcxprt_rdma (and the\nnet/ns_tracker it pinned) is leaked on every failed accept.\n\nrpcrdma_rn_register() writes rn->rn_done last, only after xa_alloc()\nand kref_get() have both succeeded, so rn_done == NULL is a natural\n\"never registered\" sentinel. Guard rpcrdma_rn_unregister() with an\nearly return when rn_done is NULL, and clear rn_done before the\nmatching xa_erase() so a repeated unregister is also a no-op.\n\nWith that guard in place, the accept errout drops the kref_init()\nbirth reference via svc_xprt_put(), which dispatches svc_rdma_free().\nTeardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing\nIS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new\nrn_done sentinel; sc_cm_id is non-NULL on every errout path because\nsvc_rdma_accept() dereferences it above the first goto errout.\n\nsvc_xprt_free() drops the module reference associated with the freed\ntransport, and svc_handle_xprt() drops its pre-acquired reference\nwhen ->xpo_accept() returns NULL. Take a replacement module reference\nbefore svc_xprt_put() so the two module_put()s remain balanced.\n\nThe rn_done guard also covers svc_rdma_free()'s non-listener call\nto rpcrdma_rn_unregister() for transports whose register attempt\nfailed or never ran."
    }
  ],
  "lastModified": "2026-09-25T05:17:00.290",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}