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CVE-2026-89702 (GCVE-0-2026-89702)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:33
VLAI
Title
nfsd: size fh_verify server sockaddr slot by xpt_locallen
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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 051382885552e12541cc0ebf82092be374a9ed2a , < 95d064f9828a20ccca5ae90a17be3e2076f25272 (git)
Affected: 051382885552e12541cc0ebf82092be374a9ed2a , < 7ff8d6363cffff45654ea85e319f7c0c54226012 (git)
Affected: 051382885552e12541cc0ebf82092be374a9ed2a , < 719a10e3f5f868c3c4ac3cf3648c5775d12034bd (git)
Affected: 051382885552e12541cc0ebf82092be374a9ed2a , < 71d068490098b1d23c63b2345e40675d3a1ca763 (git)
Affected: dcbebc86850324fbe0a993ce352f0539cd98038a (git)
Affected: 62980365d6e894234b29f44fb2bfad4f7f8bb824 (git)
Affected: 5.15.154 , < 5.16 (semver)
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Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "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."
        }
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        "shortName": "Linux"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89702",
    "datePublished": "2026-09-11T19:46:19.537Z",
    "dateReserved": "2026-09-11T19:38:34.750Z",
    "dateUpdated": "2026-09-13T06:33:23.537Z",
    "state": "PUBLISHED"
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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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/nfsd/trace.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"051382885552e12541cc0ebf82092be374a9ed2a\",\"lessThan\":\"95d064f9828a20ccca5ae90a17be3e2076f25272\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"051382885552e12541cc0ebf82092be374a9ed2a\",\"lessThan\":\"7ff8d6363cffff45654ea85e319f7c0c54226012\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"051382885552e12541cc0ebf82092be374a9ed2a\",\"lessThan\":\"719a10e3f5f868c3c4ac3cf3648c5775d12034bd\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"051382885552e12541cc0ebf82092be374a9ed2a\",\"lessThan\":\"71d068490098b1d23c63b2345e40675d3a1ca763\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"dcbebc86850324fbe0a993ce352f0539cd98038a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"62980365d6e894234b29f44fb2bfad4f7f8bb824\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5.15.154\",\"lessThan\":\"5.16\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/nfsd/trace.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-15T15:02:31+00:00",
      "cve": "CVE-2026-89702",
      "id": "CVE-2026-89702",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_affected": "200",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: nfsd: size fh_verify server sockaddr slot by xpt_locallen",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89702.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-15T23:59:51Z",
      "cve": "CVE-2026-89702",
      "id": "CVE-2026-89702",
      "initial_release_date": "2026-09-12T16:23:22Z",
      "product_status:known_affected": "114",
      "product_status:known_not_affected": "239",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89702",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89702.json",
      "version": "5"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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