CVE-2026-89702

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89702", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.750Z", "datePublished": "2026-09-11T19:46:19.537Z", "dateUpdated": "2026-10-30T12:32:45.423Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:32:45.423Z"}, "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->rq_xprt->xpt_remotelen)\n ...\n )\n TP_fast_assign(\n ...\n __assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,\n rqstp->rq_xprt->xpt_locallen);\n ...\n )\n\nWhen xpt_locallen exceeds xpt_remotelen, __assign_sockaddr's memcpy\nwrites past the reserved ring-buffer slot. In the reverse direction\n(xpt_locallen < 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's\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."}], "metrics": [{"cvssV3_1": {"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"}, "scenarios": [{"lang": "en", "value": "AV:N - The nfsd_fh_verify and nfsd_fh_verify_err tracepoints run in the in-kernel NFS server while handling NFSv2/v3 RPCs on UDP/2049; a remote packet reaches svc_udp_recvfrom, svc_process, nfsd_proc_getattr/nfsd3_proc_getattr, then fh_verify.\nAC:L - With the nfsd_fh_verify events enabled (a realistic nfsd tracing/perf deployment), every UDP fh_verify deterministically memcpy's 16 or 28 bytes of xpt_local into a 0-byte slot; no race, layout guess, or attacker-uncontrollable condition is required.\nPR:N - AUTH_NULL and AUTH_SYS verify no credentials, and GETATTR uses NFSD_MAY_NOP so a dummy filehandle still hits fh_verify (and nfsd_fh_verify_err on lookup failure); a UDP source-IP spoof or wildcard export satisfies the IP map without an authenticated principal.\nUI:N - The attacker sends crafted NFS/UDP RPCs unilaterally; no administrator or victim-client action is required at exploitation time, and tracing already being enabled is the scored configuration rather than user interaction.\nS:U - The overflow corrupts the host kernel's ftrace/perf ring buffer inside the NFS server's own kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - When the reserved sockaddr slot is larger than xpt_locallen, leftover prior ring-buffer contents including kernel pointers from other events leak to trace consumers; the UDP out-of-bounds write can also corrupt adjacent event headers so later parses treat neighbouring kernel memory as payload.\nI:H - On NFS/UDP, xpt_remotelen stays 0 so __assign_sockaddr copies 16 or 28 bytes of xpt_local past the reserved dynamic array into subsequent ring-buffer bytes and potentially the next sub-buffer page header, which is an out-of-bounds kernel write.\nA:H - Corrupting ring-buffer event headers or the next sub-buffer page metadata can oops or panic the tracer or hang consumers, and a remote peer can repeat the UDP request to force the overflow until the kernel faults."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/trace.h"], "versions": [{"version": "dcbebc86850324fbe0a993ce352f0539cd98038a", "lessThan": "4c7569ad68fc8b86ca40c7e56ef21460c0344955", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "50d9d581d2af80799125ee62617d37e9b6b476a7", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "95d064f9828a20ccca5ae90a17be3e2076f25272", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "7ff8d6363cffff45654ea85e319f7c0c54226012", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "719a10e3f5f868c3c4ac3cf3648c5775d12034bd", "status": "affected", "versionType": "git"}, {"version": "051382885552e12541cc0ebf82092be374a9ed2a", "lessThan": "71d068490098b1d23c63b2345e40675d3a1ca763", "status": "affected", "versionType": "git"}, {"version": "62980365d6e894234b29f44fb2bfad4f7f8bb824", "status": "affected", "versionType": "git"}, {"version": "5.15.154", "lessThan": "5.15.224", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/trace.h"], "versions": [{"version": "6.0", "status": "affected"}, {"version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.154", "versionEndExcluding": "5.15.224"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4c7569ad68fc8b86ca40c7e56ef21460c0344955"}, {"url": "https://git.kernel.org/stable/c/50d9d581d2af80799125ee62617d37e9b6b476a7"}, {"url": "https://git.kernel.org/stable/c/1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5"}, {"url": "https://git.kernel.org/stable/c/95d064f9828a20ccca5ae90a17be3e2076f25272"}, {"url": "https://git.kernel.org/stable/c/7ff8d6363cffff45654ea85e319f7c0c54226012"}, {"url": "https://git.kernel.org/stable/c/719a10e3f5f868c3c4ac3cf3648c5775d12034bd"}, {"url": "https://git.kernel.org/stable/c/71d068490098b1d23c63b2345e40675d3a1ca763"}], "title": "nfsd: size fh_verify server sockaddr slot by xpt_locallen", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"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->rq_xprt->xpt_remotelen)\n ...\n )\n TP_fast_assign(\n ...\n __assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,\n rqstp->rq_xprt->xpt_locallen);\n ...\n )\n\nWhen xpt_locallen exceeds xpt_remotelen, __assign_sockaddr's memcpy\nwrites past the reserved ring-buffer slot. In the reverse direction\n(xpt_locallen < 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's\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"}

{"bugzilla": {"description": "kernel: Linux kernel: nfsd out-of-bounds write and information disclosure via NFS/UDP requests", "id": "2532472", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532472"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["A flaw was found in the Linux kernel's Network File System Daemon (nfsd). When processing NFSv2/v3-over-UDP requests, the `nfsd_fh_verify` and `nfsd_fh_verify_err` tracepoints incorrectly size a memory buffer. This can lead to an out-of-bounds write, potentially allowing a remote attacker to cause a denial of service or disclose sensitive information from the kernel's ring buffer."], "name": "CVE-2026-89702", "public_date": "2026-09-11T19:46:19Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89702\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89702\nhttps://git.kernel.org/stable/c/719a10e3f5f868c3c4ac3cf3648c5775d12034bd\nhttps://git.kernel.org/stable/c/71d068490098b1d23c63b2345e40675d3a1ca763\nhttps://git.kernel.org/stable/c/7ff8d6363cffff45654ea85e319f7c0c54226012\nhttps://git.kernel.org/stable/c/95d064f9828a20ccca5ae90a17be3e2076f25272"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[051382885552e12541cc0ebf82092be374a9ed2a,95d064f9828a20ccca5ae90a17be3e2076f25272)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[051382885552e12541cc0ebf82092be374a9ed2a,71d068490098b1d23c63b2345e40675d3a1ca763)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[051382885552e12541cc0ebf82092be374a9ed2a,719a10e3f5f868c3c4ac3cf3648c5775d12034bd)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[051382885552e12541cc0ebf82092be374a9ed2a,7ff8d6363cffff45654ea85e319f7c0c54226012)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "dcbebc86850324fbe0a993ce352f0539cd98038a"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "62980365d6e894234b29f44fb2bfad4f7f8bb824"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[5.15.154,5.16)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T09:15:12.755587+00:00", "updated": "2026-09-15T20:15:14.378162+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}