{"api_version":"1","generated_at":"2026-07-28T12:20:59+00:00","cve":"CVE-2026-64399","urls":{"html":"https://cve.report/CVE-2026-64399","api":"https://cve.report/api/cve/CVE-2026-64399.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64399","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64399"},"summary":{"title":"ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file's data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp->daccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:23","updated_at":"2026-07-27 05:16:47"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe","name":"https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df","name":"https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a","name":"https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51","name":"https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6","name":"https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3","name":"https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64399","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64399","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected eb817368f50c1cbe1bd07044124aad7db6330e3a bf460ad5958d506492de4524a656439da3f99c51 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected eb817368f50c1cbe1bd07044124aad7db6330e3a 620d133d469295ee7c017ca6aafac335f65c4a5a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected eb817368f50c1cbe1bd07044124aad7db6330e3a 9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected eb817368f50c1cbe1bd07044124aad7db6330e3a baae7b39673ec21073a25e3d14f8feaada01d5df git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file's data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp->daccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T05:00:30.802Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51"},{"url":"https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a"},{"url":"https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6"},{"url":"https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df"},{"url":"https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe"},{"url":"https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3"}],"title":"ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64399","datePublished":"2026-07-25T08:50:42.925Z","dateReserved":"2026-07-19T15:36:31.785Z","dateUpdated":"2026-07-27T05:00:30.802Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:23","lastModifiedDate":"2026-07-27 05:16:47","problem_types":[],"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}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64399","Ordinal":"1","Title":"ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE","CVE":"CVE-2026-64399","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64399","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file's data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp->daccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data.","Type":"Description","Title":"ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE"}]}}}