{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64399", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.785Z", "datePublished": "2026-07-25T08:50:42.925Z", "dateUpdated": "2026-08-17T04:54:56.640Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:54:56.640Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "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 - An attacker reaches smb2_ioctl() remotely through ksmbd’s SMB service on TCP port 445.\nAC:L - The attacker directly controls both file handles, offsets, length, and request timing; no race or uncontrollable condition is required on a clone-capable filesystem.\nPR:N - A passwordless guest session on a guest-enabled share can obtain the required session, tree connection, and file handles without credentials.\nUI:N - The attacker independently negotiates the SMB session, opens the files, and submits the malicious IOCTL without victim action.\nS:U - The unauthorized file modification and any resulting code execution remain within the host kernel and services governed by the same security authority.\nC:H - In a plausible share containing service-loaded code or configuration, attacker-controlled extent replacement can yield code execution and consequent access to sensitive data.\nI:H - The attacker can overwrite arbitrary destination ranges with chosen source data despite a read-only share or a handle lacking FILE_WRITE_DATA.\nA:H - Repeated or complete corruption of critical files, databases, executables, or service configuration can cause a persistent loss of the affected system or service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "bf460ad5958d506492de4524a656439da3f99c51", "status": "affected", "versionType": "git" }, { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "620d133d469295ee7c017ca6aafac335f65c4a5a", "status": "affected", "versionType": "git" }, { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6", "status": "affected", "versionType": "git" }, { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "baae7b39673ec21073a25e3d14f8feaada01d5df", "status": "affected", "versionType": "git" }, { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "c917e4522d251071dde9871b9142d8ea1186ebfe", "status": "affected", "versionType": "git" }, { "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a", "lessThan": "388e4139db27a9e3612c9d356b826f5b1ff6a9e3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }