Authenticated memory corruption via double SMB2_CANCEL
Published Jun 25, 2026 · Updated Jun 25, 2026
Use-after-free in Linux Kernel ksmbd allows remote authenticated users to corrupt kernel memory through two SMB2_CANCEL requests. When the first cancellation frees a deferred file_lock, the worker leaves its async request linked with smb2_remove_blocked_lock and the freed pointer still registered; smb2_cancel then invokes that callback again for the same AsyncId. An authenticated SMB client must first create a blocking SMB2_LOCK and send the second cancellation before connection teardown; the published reproducer confirms KASAN-detected memory corruption but does not demonstrate code execution.
Summary
What happened
Use-after-free in Linux Kernel ksmbd allows remote authenticated users to corrupt kernel memory through two SMB2_CANCEL requests. When the first cancellation frees a deferred file_lock, the worker leaves its async request linked with smb2_remove_blocked_lock and the freed pointer still registered; smb2_cancel then invokes that callback again for the same AsyncId. An authenticated SMB client must first create a blocking SMB2_LOCK and send the second cancellation before connection teardown; the published reproducer confirms KASAN-detected memory corruption but does not demonstrate code execution.
The record
- CVE
- CVE-2026-53198
- Published
- Jun 25, 2026
- Updated
- Jun 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1210
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 25, 2026CVE publishedPublication date reported by the CVE source.
- Jun 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 <6.1.176
- Affected versionversion=0 <6.12.94
- Affected versionversion=0 <6.18.36
- Affected versionversion=0 <6.6.143
- Affected versionversion=0 <7.0.13
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <14d2eee0193ac3cd1bf3d014373449f0b8d35d6d
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <89ae9df09d2c1fb4a4eb495c113a7ce1dca34147
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b7063c7426ea5a4d15e01b60538718765392f49d
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f580d27e8928828693df44ba2db0fffdbe11dfea
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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