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Review reviewCritical

CVE-2026-64397

Linux

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. T...

CVSS
9.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.25
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 9.8

Vulnerability overview

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. T...

Affected product and versions

Product
Linux
Affected versions
>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 1426fd79102539bc0ab5c8fced047ad4313b9908, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 2a64dbf9c739ddf7a25a066507597bf89f8f73d2, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 64dac2d486ec1eb18dc00968b16a230b6b75ec24, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < fd22b039a5a05bc1d6818e9dcd1001fb432a829d, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < be6d26bf27499977c746abc163659915082348d8, >= 5.15
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Not available