CVE-2026-64397
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: serialize QUERY_DIRECTORY requests per file
smb2_query_dir() stores a pointer to its stack-allocated private data in
the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the
same file handle can overwrite this pointer while an iterate_dir() callback
is still using it, resulting in a stack use-after-free.
Add a per-file mutex and hold it while accessing the shared directory
enumeration state. The lock covers scan restart, dot entry state,
readdir_data setup and iteration, and response construction. This prevents
another request from replacing readdir_data.private before the current
request has finished using it and also serializes the shared file position.
CSIRTS triage
- What
- The vulnerability involves improper serialization of QUERY_DIRECTORY requests per file in ksmbd.
- Who is affected
- Users of ksmbd are affected by this issue.
- Urgency
- Remediation is important to ensure proper handling of directory queries.
- Action
- Implement the fix for QUERY_DIRECTORY request serialization.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.48% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 39% of all EPSS-scored CVEs.
Advisory coverage (2)
- criticalCVE-2026-64397: In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize QUERY_DIR…nvd · 2026-07-25
- mediumCVE-2026-64397: ksmbd: serialize QUERY_DIRECTORY requests per filemsrc · 2026-07-14
External references
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