{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64395","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T15:36:31.785Z","datePublished":"2026-07-25T08:50:40.393Z","dateUpdated":"2026-08-17T04:54:49.007Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T04:54:49.007Z"},"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."}],"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."}]}],"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":"2d2ab6983620c2d60ce7db72133984ca3873b929","status":"affected","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","lessThan":"67bdad9cf01b25030e3bf00bbce6c309319d6663","status":"affected","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","lessThan":"b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f","status":"affected","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","lessThan":"db231af842868268839f9f9619c68cb27830d8be","status":"affected","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","lessThan":"a10942af27832c2761d020863a46e79bebe0567d","status":"affected","versionType":"git"},{"version":"eb817368f50c1cbe1bd07044124aad7db6330e3a","lessThan":"cedff600f1642aa982178503552f0d007bc829c8","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/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"}],"title":"ksmbd: require source read access for duplicate extents","x_generator":{"engine":"bippy-1.2.0"}}}}