Kernel memory disclosure via unvalidated inherited SIDs
Published Jul 19, 2026 · Updated Jul 19, 2026
Out-of-bounds read in Linux Kernel ksmbd allows remote authenticated users to disclose kernel heap memory through SMB2 CREATE requests. During ACL inheritance, ksmbd computes and copies the parent security.NTACL Owner and Group SIDs without first validating their encoded bounds. An authenticated SMB user with share write access can plant a malformed descriptor and create a child file, retrieving leaked memory or triggering a kernel oops or panic.
Summary
What happened
Out-of-bounds read in Linux Kernel ksmbd allows remote authenticated users to disclose kernel heap memory through SMB2 CREATE requests. During ACL inheritance, ksmbd computes and copies the parent security.NTACL Owner and Group SIDs without first validating their encoded bounds. An authenticated SMB user with share write access can plant a malformed descriptor and create a child file, retrieving leaked memory or triggering a kernel oops or panic.
The record
- CVE
- CVE-2026-64138
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <6.12.92
- Affected versionversion=0 <6.18.34
- Affected versionversion=0 <7.0.11
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <18d8db24b0a5b7be4829238dd4022236df02d421
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1c9d0646a9959752f11ca1080dc1ff26bd1756cb
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <69f030cf95488ae1186c72ac8c66fd279664ea7f
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f0e5c9c663badc9982e6941322eef1cb17de0f11
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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