CVE-2026-89530

Estado: RecibidaCrítica (9.8)—

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

svcrdma: Reject inline replies that overflow the pull-up buffer

An RPC-over-RDMA client can request a reply, such as an NFS READ payload, without providing a Write list or a Reply chunk to carry it. When such a reply needs more scatter/gather entries than the device's Send Queue supports, svc_rdma_pull_up_needed() selects pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole reply into sctxt->sc_xprt_buf.

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That buffer is only sc_max_req_size bytes, while the reply on this path is bounded only by the client's request, so svc_rdma_xb_linearize() copies past the end of the buffer and corrupts adjacent slab memory. The oversized length is then stored in sc_sges[0].length and posted, so the device also reads beyond the mapped region.

The SGE-exhaustion branch is the only pull-up path that can exceed the buffer: the threshold branch pulls up only replies smaller than RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE budget are sent directly without linearization. Make svc_rdma_pull_up_needed() report -E2BIG when the reply it would pull up cannot fit sc_max_req_size, and fail the request with ERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping the connection.

The helper no longer answers a simple yes/no question: it now reports pull-up, no pull-up, or -E2BIG for a reply too large to linearize. Rename svc_rdma_pull_up_needed() to svc_rdma_check_pull_up() so its name no longer implies a boolean predicate.

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: 0.46%
Percentil entre todas las CVEs puntuadas: 37
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1565.001 Stored Data Manipulationimpact70 %

Vulnerabilidad en kernel Linux (AV:N/PR:N/UI:N) explotable remotamente por cliente RPC-over-RDMA (T1190). Desbordamiento de buffer en memoria causa corrupción (T1565.001) y potencial denegación de servicio (T1499.004) al leer más allá de región mapeada.

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 Vulnerability Scanning Restrict File and Directory Permissions Privileged Account Management Remote Data Storage Network Segmentation

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-2026-89530",
  "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": "e248aa7be86e8179f20ac0931774ecd746f3f5bf",
              "lessThan": "fcd91b9957462d398792201c239dffaeff1cc8b2",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e248aa7be86e8179f20ac0931774ecd746f3f5bf",
              "lessThan": "1949dd1576f7a8aa161b1330c6125df9d53046d5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e248aa7be86e8179f20ac0931774ecd746f3f5bf",
              "lessThan": "8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e248aa7be86e8179f20ac0931774ecd746f3f5bf",
              "lessThan": "0fbe20dfe74b783d255bf389a6ea77aa25dc7860",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9b65b18f817d9ada2bf67351f24bdcce6789a0bb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d564356e1919d1178568c19af410cfc1a9076663",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4.19.22",
              "lessThan": "4.20",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "4.20.9",
              "lessThan": "4.21",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "net/sunrpc/xprtrdma/svc_rdma_sendto.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.0",
              "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/svc_rdma_sendto.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:35.850",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0fbe20dfe74b783d255bf389a6ea77aa25dc7860",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1949dd1576f7a8aa161b1330c6125df9d53046d5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fcd91b9957462d398792201c239dffaeff1cc8b2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Reject inline replies that overflow the pull-up buffer\n\nAn RPC-over-RDMA client can request a reply, such as an NFS READ\npayload, without providing a Write list or a Reply chunk to carry\nit. When such a reply needs more scatter/gather entries than the\ndevice's Send Queue supports, svc_rdma_pull_up_needed() selects\npull-up and svc_rdma_pull_up_reply_msg() linearizes the whole\nreply into sctxt->sc_xprt_buf. That buffer is only sc_max_req_size\nbytes, while the reply on this path is bounded only by the client's\nrequest, so svc_rdma_xb_linearize() copies past the end of the\nbuffer and corrupts adjacent slab memory. The oversized length is\nthen stored in sc_sges[0].length and posted, so the device also\nreads beyond the mapped region.\n\nThe SGE-exhaustion branch is the only pull-up path that can exceed\nthe buffer: the threshold branch pulls up only replies smaller\nthan RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE\nbudget are sent directly without linearization. Make\nsvc_rdma_pull_up_needed() report -E2BIG when the reply it would\npull up cannot fit sc_max_req_size, and fail the request with\nERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping\nthe connection.\n\nThe helper no longer answers a simple yes/no question: it now\nreports pull-up, no pull-up, or -E2BIG for a reply too large to\nlinearize. Rename svc_rdma_pull_up_needed() to\nsvc_rdma_check_pull_up() so its name no longer implies a boolean\npredicate."
    }
  ],
  "lastModified": "2026-09-13T07:17:15.237",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}