FKIE_CVE-2025-40210

Vulnerability from fkie_nvd - Published: 2025-11-21 11:15 - Updated: 2026-10-19 19:10
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND" I've found that pynfs COMP6 now leaves the connection or lease in a strange state, which causes CLOSE9 to hang indefinitely. I've dug into it a little, but I haven't been able to root-cause it yet. However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"). Tianshuo Han also reports a potential vulnerability when decoding an NFSv4 COMPOUND. An attacker can place an arbitrarily large op count in the COMPOUND header, which results in: [ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0 when NFSD attempts to allocate the COMPOUND op array. Let's restore the operation-per-COMPOUND limit, but increased to 200 for now.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3e7f011c255582d7c914133785bbba1990441713
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b3ee7ce432289deac87b9d14e01f2fe6958f7f0b
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c",
            "fs/nfsd/nfs4state.c",
            "fs/nfsd/nfs4xdr.c",
            "fs/nfsd/nfsd.h",
            "fs/nfsd/xdr4.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b3ee7ce432289deac87b9d14e01f2fe6958f7f0b",
              "status": "affected",
              "version": "48aab1606fa80027143a445224f552b4eeea845b",
              "versionType": "git"
            },
            {
              "lessThan": "3e7f011c255582d7c914133785bbba1990441713",
              "status": "affected",
              "version": "48aab1606fa80027143a445224f552b4eeea845b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4proc.c",
            "fs/nfsd/nfs4state.c",
            "fs/nfsd/nfs4xdr.c",
            "fs/nfsd/nfsd.h",
            "fs/nfsd/xdr4.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"NFSD: Remove the cap on number of operations per NFSv4 COMPOUND\"\n\nI\u0027ve found that pynfs COMP6 now leaves the connection or lease in a\nstrange state, which causes CLOSE9 to hang indefinitely. I\u0027ve dug\ninto it a little, but I haven\u0027t been able to root-cause it yet.\nHowever, I bisected to commit 48aab1606fa8 (\"NFSD: Remove the cap on\nnumber of operations per NFSv4 COMPOUND\").\n\nTianshuo Han also reports a potential vulnerability when decoding\nan NFSv4 COMPOUND. An attacker can place an arbitrarily large op\ncount in the COMPOUND header, which results in:\n\n[   51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total\npages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO),\nnodemask=(null),cpuset=/,mems_allowed=0\n\nwhen NFSD attempts to allocate the COMPOUND op array.\n\nLet\u0027s restore the operation-per-COMPOUND limit, but increased to 200\nfor now."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nRevertir \u0027NFSD: Remove the cap on number of operations per NFSv4 COMPOUND\u0027\n\nHe descubierto que pynfs COMP6 ahora deja la conexi\u00f3n o el arrendamiento en un estado extra\u00f1o, lo que provoca que CLOSE9 se cuelgue indefinidamente. He investigado un poco, pero a\u00fan no he podido determinar la causa ra\u00edz. Sin embargo, hice una b\u00fasqueda binaria hasta el commit 48aab1606fa8 (\u0027NFSD: Remove the cap on number of operations per NFSv4 COMPOUND\u0027).\n\nTianshuo Han tambi\u00e9n informa una posible vulnerabilidad al decodificar un COMPOUND NFSv4. Un atacante puede colocar un recuento de operaciones arbitrariamente grande en la cabecera del COMPOUND, lo que resulta en:\n\n[ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0\n\ncuando NFSD intenta asignar el array de operaciones del COMPOUND.\n\nRestauremos el l\u00edmite de operaciones por COMPOUND, pero aumentado a 200 por ahora."
    }
  ],
  "id": "CVE-2025-40210",
  "lastModified": "2026-10-19T19:10:00.130",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2025-11-21T11:15:49.110",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e7f011c255582d7c914133785bbba1990441713"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b3ee7ce432289deac87b9d14e01f2fe6958f7f0b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}



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