CVE-2025-40210 (GCVE-0-2025-40210)

Vulnerability from cvelistv5 – Published: 2025-11-21 10:21 – Updated: 2025-12-01 06:20
VLAI?
Title
Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b3ee7ce432289deac87b9d14e01f2fe6958f7f0b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3e7f011c255582d7c914133785bbba1990441713 (git)
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    Linux Linux Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
          "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",
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          "vendor": "Linux",
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            }
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          "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-01T06:20:15.375Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/b3ee7ce432289deac87b9d14e01f2fe6958f7f0b"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e7f011c255582d7c914133785bbba1990441713"
        }
      ],
      "title": "Revert \"NFSD: Remove the cap on number of operations per NFSv4 COMPOUND\"",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40210",
    "datePublished": "2025-11-21T10:21:35.540Z",
    "dateReserved": "2025-04-16T07:20:57.179Z",
    "dateUpdated": "2025-12-01T06:20:15.375Z",
    "state": "PUBLISHED"
  },
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    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40210\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-11-21T11:15:49.110\",\"lastModified\":\"2025-11-21T15:13:13.800\",\"vulnStatus\":\"Awaiting Analysis\",\"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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3e7f011c255582d7c914133785bbba1990441713\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b3ee7ce432289deac87b9d14e01f2fe6958f7f0b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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