{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64138","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.037Z","datePublished":"2026-07-19T15:40:31.760Z","dateUpdated":"2026-08-05T12:39:39.447Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:39:39.447Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate SID in parent security descriptor during ACL inheritance\n\nIntroduce smb_validate_ntsd_sid() helper to safely validate Owner SID\nand Group SID inside the NT Security Descriptor (smb_ntsd) retrieved\nfrom the parent directory."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable code runs in ksmbd's in-kernel SMB server, reachable by remote attackers sending SMB2 CREATE requests over TCP port 445 after session establishment.\nAC:L - An authenticated attacker with share write access can plant a malformed parent security.NTACL xattr and reliably trigger the bug by creating a child file; they control both the crafted on-disk descriptor and the concurrent SMB request that exercises inheritance.\nPR:L - Exploitation requires an authenticated SMB2 session with write permission on the parent directory to create files; this is not a pre-authentication code path but does not require host root or special kernel capabilities.\nUI:N - Exploitation is fully automated over the SMB protocol and does not require any action from a separate victim user beyond normal server operation.\nS:U - The vulnerability is confined to the kernel's ksmbd security context and does not cross a VM, container, or IOMMU security boundary.\nC:H - The unchecked SID size computation and memcpy perform an out-of-bounds kernel heap read; stolen memory can be embedded in the newly created file's security descriptor and retrieved by the attacker.\nI:H - Unvalidated out-of-bounds memory access is a memory corruption primitive in kernel context; per kernel CVSS guidance, such bugs are scored at High integrity impact even when the immediate fault is a read.\nA:H - Reading from attacker-controlled out-of-bounds offsets can dereference unmapped or invalid kernel memory, causing an oops or panic and denying SMB 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/smbacl.c"],"versions":[{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"f0e5c9c663badc9982e6941322eef1cb17de0f11","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"18d8db24b0a5b7be4829238dd4022236df02d421","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"1c9d0646a9959752f11ca1080dc1ff26bd1756cb","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"69f030cf95488ae1186c72ac8c66fd279664ea7f","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/smbacl.c"],"versions":[{"version":"5.15","status":"affected"},{"version":"0","lessThan":"5.15","status":"unaffected","versionType":"semver"},{"version":"6.12.92","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.34","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11"},{"url":"https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421"},{"url":"https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb"},{"url":"https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f"}],"title":"ksmbd: validate SID in parent security descriptor during ACL inheritance","x_generator":{"engine":"bippy-1.2.0"}}}}