CVE-2026-45983 (GCVE-0-2026-45983)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:18 – Updated: 2026-05-27 12:18
VLAI
Title
nfsd: never defer requests during idmap lookup
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: never defer requests during idmap lookup During v4 request compound arg decoding, some ops (e.g. SETATTR) can trigger idmap lookup upcalls. When those upcall responses get delayed beyond the allowed time limit, cache_check() will mark the request for deferral and cause it to be dropped. This prevents nfs4svc_encode_compoundres from being executed, and thus the session slot flag NFSD4_SLOT_INUSE never gets cleared. Subsequent client requests will fail with NFSERR_JUKEBOX, given that the slot will be marked as in-use, making the SEQUENCE op fail. Fix this by making sure that the RQ_USEDEFERRAL flag is always clear during nfs4svc_decode_compoundargs(), since no v4 request should ever be deferred.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < b9abb760db20504240a7147f27934d900cd80b23 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < 3a72c7dedc99b321e0f267e4e999e5baf07c4593 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < 99e17b20fddac19a228d213e00f6b9e1c10daff9 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < 243f71ed873ff3feeb6f9b5cb145d63f7188b4c4 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < 063a6f22478ef929625000a2caf54667725c1dfd (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < d75ec4504a4340b033b15cad0303988b3089dd93 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < 8dff54fe88c0dcd4c55bff9fc2fa6ca968290826 (git)
Affected: 2f425878b6a71571341dcd3f9e9d1a6f6355da9c , < f9c206cdc4266caad6a9a7f46341420a10f03ccb (git)
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Linux Linux Affected: 2.6.30
Unaffected: 0 , < 2.6.30 (semver)
Unaffected: 5.10.252 , ≤ 5.10.* (semver)
Unaffected: 5.15.202 , ≤ 5.15.* (semver)
Unaffected: 6.1.165 , ≤ 6.1.* (semver)
Unaffected: 6.6.128 , ≤ 6.6.* (semver)
Unaffected: 6.12.75 , ≤ 6.12.* (semver)
Unaffected: 6.18.14 , ≤ 6.18.* (semver)
Unaffected: 6.19.4 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4idmap.c",
            "fs/nfsd/nfs4proc.c",
            "fs/nfsd/nfs4xdr.c"
          ],
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          "vendor": "Linux",
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            "fs/nfsd/nfs4xdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "2.6.30"
            },
            {
              "lessThan": "2.6.30",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
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            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.202",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
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              "versionType": "semver"
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            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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              "negate": false,
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: never defer requests during idmap lookup\n\nDuring v4 request compound arg decoding, some ops (e.g. SETATTR)\ncan trigger idmap lookup upcalls. When those upcall responses get\ndelayed beyond the allowed time limit, cache_check() will mark the\nrequest for deferral and cause it to be dropped.\n\nThis prevents nfs4svc_encode_compoundres from being executed, and\nthus the session slot flag NFSD4_SLOT_INUSE never gets cleared.\nSubsequent client requests will fail with NFSERR_JUKEBOX, given\nthat the slot will be marked as in-use, making the SEQUENCE op\nfail.\n\nFix this by making sure that the RQ_USEDEFERRAL flag is always\nclear during nfs4svc_decode_compoundargs(), since no v4 request\nshould ever be deferred."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:18:41.619Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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      ],
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45983",
    "datePublished": "2026-05-27T12:18:41.619Z",
    "dateReserved": "2026-05-13T15:03:33.090Z",
    "dateUpdated": "2026-05-27T12:18:41.619Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-05-29",
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      "percentile": "0.07393"
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  }
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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