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CVE-2026-89545

Estado: RecibidaAlta (7.8)—

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

sunrpc: defer rq_argp and rq_resp free until after RCU grace period

svc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously via kfree(), but defers the rqstp struct free via kfree_rcu(). After svc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is a window where RCU readers that started before list_del_rcu() can still traverse the thread list and find the rqstp. These readers (e.g. nfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has already been freed — a use-after-free.

Fix this by moving the kfree of rq_argp and rq_resp into an explicit call_rcu() callback alongside the struct free. Resources not accessed by RCU readers (bvec, buffer pages, scratch folio, auth_data) remain synchronously freed.

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 local (AV:L, PR:L) de use-after-free en el kernel Linux que permite a un atacante local provocar DoS mediante crash del sistema (confidencialidad e integridad también afectadas).

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 ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate 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 KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89545",
  "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": "812443865c5fc255363d4a684a62c086af1addca",
              "lessThan": "0ea49d69aa806008b2424c8cf21cf746b9963967",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "812443865c5fc255363d4a684a62c086af1addca",
              "lessThan": "08bc49e0541260bf294962cf889a32a2d2713ad6",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "812443865c5fc255363d4a684a62c086af1addca",
              "lessThan": "e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "812443865c5fc255363d4a684a62c086af1addca",
              "lessThan": "c479bde671cbe2f9e152834a8b0eb7c3c295bbaf",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sunrpc/svc.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.19"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.19",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "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/svc.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:37.840",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/08bc49e0541260bf294962cf889a32a2d2713ad6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0ea49d69aa806008b2424c8cf21cf746b9963967",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c479bde671cbe2f9e152834a8b0eb7c3c295bbaf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: defer rq_argp and rq_resp free until after RCU grace period\n\nsvc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously\nvia kfree(), but defers the rqstp struct free via kfree_rcu().  After\nsvc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is\na window where RCU readers that started before list_del_rcu() can still\ntraverse the thread list and find the rqstp.  These readers (e.g.\nnfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has\nalready been freed — a use-after-free.\n\nFix this by moving the kfree of rq_argp and rq_resp into an explicit\ncall_rcu() callback alongside the struct free.  Resources not accessed\nby RCU readers (bvec, buffer pages, scratch folio, auth_data) remain\nsynchronously freed."
    }
  ],
  "lastModified": "2026-09-21T14:17:23.150",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}