{"id":"CVE-2026-64395","state":"PUBLISHED","title":"ksmbd: require source read access for duplicate extents","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require source read access for duplicate extents\n\nFSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to\nvfs_clone_file_range() or vfs_copy_file_range() without checking the SMB\naccess mask granted to the source handle. A handle opened with attribute\naccess can consequently be used to copy file contents into an\nattacker-readable destination.\n\nRequire FILE_READ_DATA on the source handle before either VFS operation,\nmatching other ksmbd data-copy paths.","publishedAt":"2026-07-25T08:50:40.393Z","updatedAt":"2026-08-17T04:54:49.007Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"2d2ab6983620c2d60ce7db72133984ca3873b929","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"67bdad9cf01b25030e3bf00bbce6c309319d6663","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"db231af842868268839f9f9619c68cb27830d8be","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"a10942af27832c2761d020863a46e79bebe0567d","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"cedff600f1642aa982178503552f0d007bc829c8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2pdu.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2pdu.c"]}],"references":["https://git.kernel.org/stable/c/2d2ab6983620c2d60ce7db72133984ca3873b929","https://git.kernel.org/stable/c/67bdad9cf01b25030e3bf00bbce6c309319d6663","https://git.kernel.org/stable/c/b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f","https://git.kernel.org/stable/c/db231af842868268839f9f9619c68cb27830d8be","https://git.kernel.org/stable/c/a10942af27832c2761d020863a46e79bebe0567d","https://git.kernel.org/stable/c/cedff600f1642aa982178503552f0d007bc829c8"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64395.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64395","state":"PUBLISHED","datePublished":"2026-07-25T08:50:40.393Z","dateUpdated":"2026-08-17T04:54:49.007Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.785Z"},"containers":{"cna":{"title":"ksmbd: require source read access for duplicate extents","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require source read access for duplicate extents\n\nFSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to\nvfs_clone_file_range() or vfs_copy_file_range() without checking the SMB\naccess mask granted to the source handle. A handle opened with attribute\naccess can consequently be used to copy file contents into an\nattacker-readable destination.\n\nRequire FILE_READ_DATA on the source handle before either VFS operation,\nmatching other ksmbd data-copy paths."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"2d2ab6983620c2d60ce7db72133984ca3873b929","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"67bdad9cf01b25030e3bf00bbce6c309319d6663","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"db231af842868268839f9f9619c68cb27830d8be","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"a10942af27832c2761d020863a46e79bebe0567d","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","status":"affected","lessThan":"cedff600f1642aa982178503552f0d007bc829c8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2pdu.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2pdu.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2d2ab6983620c2d60ce7db72133984ca3873b929"},{"url":"https://git.kernel.org/stable/c/67bdad9cf01b25030e3bf00bbce6c309319d6663"},{"url":"https://git.kernel.org/stable/c/b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f"},{"url":"https://git.kernel.org/stable/c/db231af842868268839f9f9619c68cb27830d8be"},{"url":"https://git.kernel.org/stable/c/a10942af27832c2761d020863a46e79bebe0567d"},{"url":"https://git.kernel.org/stable/c/cedff600f1642aa982178503552f0d007bc829c8"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable SMB2 IOCTL is remotely reachable through ksmbd over TCP, normally port 445.\nAC:L - The attacker controls both handles, offsets, and copy length; no race is required, and exploitation is reliable on common reflink-capable filesystems such as XFS and Btrfs.\nPR:N - In a reasonable guest-enabled writable-share deployment, an unauthenticated remote attacker can establish a guest session without credentials and obtain the required attribute-only source and writable destination handles.\nUI:N - After connecting to the share, the attacker can open both handles and issue the IOCTL without any victim action.\nS:U - The bypass discloses files governed by the same kernel and SMB server security authority and does not cross a virtualization or other security scope.\nC:H - Attacker-controlled offsets and lengths allow complete copying of otherwise unreadable files into an attacker-readable destination, causing total confidentiality loss for protected share contents.\nI:N - The source is not modified, and the destination must already be on a writable tree and opened with FILE_WRITE_DATA, so the flaw adds no unauthorized modification capability.\nA:N - The operation does not corrupt memory, crash the kernel, or inherently disrupt service; any destination writes are already authorized by the required handle permissions."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:54:49.007Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}