FKIE_CVE-2026-89702

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-10-30 13:20
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: size fh_verify server sockaddr slot by xpt_locallen The nfsd_fh_verify and nfsd_fh_verify_err tracepoints declare the server sockaddr slot sized by xpt_remotelen but fill it from xpt_local using xpt_locallen: TP_STRUCT__entry( ... __sockaddr(server, rqstp->rq_xprt->xpt_remotelen) ... ) TP_fast_assign( ... __assign_sockaddr(server, &rqstp->rq_xprt->xpt_local, rqstp->rq_xprt->xpt_locallen); ... ) When xpt_locallen exceeds xpt_remotelen, __assign_sockaddr's memcpy writes past the reserved ring-buffer slot. In the reverse direction (xpt_locallen < xpt_remotelen) the slot is oversized and the unwritten tail leaks prior ring-buffer contents to trace consumers. The write-past-end case is reachable on NFS/UDP. svc_xprt_set_remote() is only called from svc_tcp_accept() (net/sunrpc/svcsock.c) and from the RDMA connect path; svc_create_socket() for UDP calls only svc_xprt_set_local(), so xpt_remotelen stays 0 for the xprt's lifetime. Every fh_verify trace for an NFSv2/v3-over-UDP request then copies 16 or 28 bytes from xpt_local into a zero-byte slot. The other NFSD tracepoints that record the server address (NFSD_TRACE_PROC_CALL_FIELDS, NFSD_TRACE_PROC_RES_FIELDS, SVC_RQST_ENDPOINT_FIELDS) already size the server slot by xpt_locallen; nfsd_fh_verify and nfsd_fh_verify_err were the only exceptions. Fix by sizing the server slot with xpt_locallen so the declared slot matches the copy length. The client slot and its assignment already agree on xpt_remotelen and are left untouched.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4c7569ad68fc8b86ca40c7e56ef21460c0344955
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/50d9d581d2af80799125ee62617d37e9b6b476a7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/719a10e3f5f868c3c4ac3cf3648c5775d12034bd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/71d068490098b1d23c63b2345e40675d3a1ca763
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ff8d6363cffff45654ea85e319f7c0c54226012
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/95d064f9828a20ccca5ae90a17be3e2076f25272
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/trace.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4c7569ad68fc8b86ca40c7e56ef21460c0344955",
              "status": "affected",
              "version": "dcbebc86850324fbe0a993ce352f0539cd98038a",
              "versionType": "git"
            },
            {
              "lessThan": "50d9d581d2af80799125ee62617d37e9b6b476a7",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "lessThan": "1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "lessThan": "95d064f9828a20ccca5ae90a17be3e2076f25272",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "lessThan": "7ff8d6363cffff45654ea85e319f7c0c54226012",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "lessThan": "719a10e3f5f868c3c4ac3cf3648c5775d12034bd",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "lessThan": "71d068490098b1d23c63b2345e40675d3a1ca763",
              "status": "affected",
              "version": "051382885552e12541cc0ebf82092be374a9ed2a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "62980365d6e894234b29f44fb2bfad4f7f8bb824",
              "versionType": "git"
            },
            {
              "lessThan": "5.15.224",
              "status": "affected",
              "version": "5.15.154",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/trace.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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\nnfsd: size fh_verify server sockaddr slot by xpt_locallen\n\nThe nfsd_fh_verify and nfsd_fh_verify_err tracepoints declare the\nserver sockaddr slot sized by xpt_remotelen but fill it from\nxpt_local using xpt_locallen:\n\n    TP_STRUCT__entry(\n            ...\n            __sockaddr(server, rqstp-\u003erq_xprt-\u003expt_remotelen)\n            ...\n    )\n    TP_fast_assign(\n            ...\n            __assign_sockaddr(server, \u0026rqstp-\u003erq_xprt-\u003expt_local,\n                              rqstp-\u003erq_xprt-\u003expt_locallen);\n            ...\n    )\n\nWhen xpt_locallen exceeds xpt_remotelen, __assign_sockaddr\u0027s memcpy\nwrites past the reserved ring-buffer slot. In the reverse direction\n(xpt_locallen \u003c xpt_remotelen) the slot is oversized and the\nunwritten tail leaks prior ring-buffer contents to trace consumers.\n\nThe write-past-end case is reachable on NFS/UDP. svc_xprt_set_remote()\nis only called from svc_tcp_accept() (net/sunrpc/svcsock.c) and from\nthe RDMA connect path; svc_create_socket() for UDP calls only\nsvc_xprt_set_local(), so xpt_remotelen stays 0 for the xprt\u0027s\nlifetime. Every fh_verify trace for an NFSv2/v3-over-UDP request\nthen copies 16 or 28 bytes from xpt_local into a zero-byte slot.\n\nThe other NFSD tracepoints that record the server address\n(NFSD_TRACE_PROC_CALL_FIELDS, NFSD_TRACE_PROC_RES_FIELDS,\nSVC_RQST_ENDPOINT_FIELDS) already size the server slot by\nxpt_locallen; nfsd_fh_verify and nfsd_fh_verify_err were the only\nexceptions.\n\nFix by sizing the server slot with xpt_locallen so the declared slot\nmatches the copy length. The client slot and its assignment already\nagree on xpt_remotelen and are left untouched."
    }
  ],
  "id": "CVE-2026-89702",
  "lastModified": "2026-10-30T13:20:26.800",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:57.413",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4c7569ad68fc8b86ca40c7e56ef21460c0344955"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/50d9d581d2af80799125ee62617d37e9b6b476a7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/719a10e3f5f868c3c4ac3cf3648c5775d12034bd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/71d068490098b1d23c63b2345e40675d3a1ca763"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7ff8d6363cffff45654ea85e319f7c0c54226012"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/95d064f9828a20ccca5ae90a17be3e2076f25272"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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