CVE-2026-64397
Linux Kernel use-after-free
- Published25 Jul 2026
Description
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
Remediation
- https://git.kernel.org/stable/c/1426fd79102539bc0ab5c8fced047ad4313b9908
- https://git.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2
- https://git.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24
- https://git.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199
- https://git.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8
- https://git.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d
References
- https://git.kernel.org/stable/c/1426fd79102539bc0ab5c8fced047ad4313b9908
- https://git.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2
- https://git.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24
- https://git.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199
- https://git.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8
- https://git.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-64397 being actively exploited?
CVE-2026-64397 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.70%.
How severe is CVE-2026-64397?
CVE-2026-64397 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.70% probability of exploitation.
Which products are affected by CVE-2026-64397?
Affected products include Linux Kernel.
How do I fix CVE-2026-64397?
Upgrade affected software to a fixed version, for example Linux Kernel 6.1.178 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.