Kernel memory corruption via concurrent directory queries
Published Jul 25, 2026 · Updated Jul 25, 2026
Use-after-free in Linux Kernel ksmbd allows remote attackers to corrupt kernel memory via concurrent SMB2 QUERY_DIRECTORY requests. smb2_query_dir stores a stack-private pointer in shared readdir_data, which another request can replace while an iteration callback still uses it. A valid session, tree connection, and readable directory handle are required, although a guest-readable share permits unauthenticated triggering; effects include memory disclosure, arbitrary corruption, or kernel panic.
Summary
What happened
Use-after-free in Linux Kernel ksmbd allows remote attackers to corrupt kernel memory via concurrent SMB2 QUERY_DIRECTORY requests. smb2_query_dir stores a stack-private pointer in shared readdir_data, which another request can replace while an iteration callback still uses it. A valid session, tree connection, and readable directory handle are required, although a guest-readable share permits unauthenticated triggering; effects include memory disclosure, arbitrary corruption, or kernel panic.
The record
- CVE
- CVE-2026-64397
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 25, 2026CVE publishedPublication date reported by the CVE source.
- Jul 25, 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 <6.1.178
- Affected versionversion=0 <6.12.96
- Affected versionversion=0 <6.18.39
- Affected versionversion=0 <6.6.145
- Affected versionversion=0 <7.1.4
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1426fd79102539bc0ab5c8fced047ad4313b9908
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2a64dbf9c739ddf7a25a066507597bf89f8f73d2
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <64dac2d486ec1eb18dc00968b16a230b6b75ec24
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <be6d26bf27499977c746abc163659915082348d8
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fd22b039a5a05bc1d6818e9dcd1001fb432a829d
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Technologies
Your stack
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