Out-of-share file creation via caseless retry
Published Jul 25, 2026 · Updated Jul 25, 2026
Path traversal in affected Linux Kernel releases allows remote attackers to create empty files or directories outside writable SMB shares. In caseless mode, __ksmbd_vfs_kern_path() treats a LOOKUP_BENEATH -EXDEV escape rejection as a missing path and reconstructs it for retry. Write-capable share access is required; guest access is sufficient where enabled, and the flaw exposes limited pathname metadata but cannot supply file contents or overwrite existing data.
Summary
What happened
Path traversal in affected Linux Kernel releases allows remote attackers to create empty files or directories outside writable SMB shares. In caseless mode, __ksmbd_vfs_kern_path() treats a LOOKUP_BENEATH -EXDEV escape rejection as a missing path and reconstructs it for retry. Write-capable share access is required; guest access is sufficient where enabled, and the flaw exposes limited pathname metadata but cannot supply file contents or overwrite existing data.
The record
- CVE
- CVE-2026-64400
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1083
- 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 <7.1.4
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <54bab9ba5a9f156ffa9324fcbe5a356fd0242f95
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8c9a4f1327eb71efbf14842e7b8a6d965077eb67
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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