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CVE-2026-64397

9.8 · CRITICAL

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…

Published Jul 25, 2026EPSS 0.48%

Overview

CVE-2026-64397 is a critical-severity vulnerability. It was published on July 25, 2026 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/1426fd79102539bc0ab5c8fced047ad4313b9908Refgit.kernel.org/stable/c/2a64dbf9c739ddf7a25a066507597bf89f8f73d2Refgit.kernel.org/stable/c/64dac2d486ec1eb18dc00968b16a230b6b75ec24Refgit.kernel.org/stable/c/a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199Refgit.kernel.org/stable/c/be6d26bf27499977c746abc163659915082348d8Refgit.kernel.org/stable/c/fd22b039a5a05bc1d6818e9dcd1001fb432a829d

How CyberStrike helps

Frequently asked questions

What is CVE-2026-64397?

CVE-2026-64397 is a critical-severity vulnerability. It was published on July 25, 2026 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-64397?

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-64397?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-64397?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-64397 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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