# CVE-2026-64397: linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: serialize QUERY_DIRECTORY requests per fi...

CVE-2026-64397 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-64397, released July 26, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-64397
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0048
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.180-1 | [DEBIAN-CVE-2026-64397](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64397.md) | Jul 26, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.96-1 | [DEBIAN-CVE-2026-64397](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64397.md) | Jul 26, 2026 |
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64397](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64397.md) | Jul 26, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.100-1~deb12u1 | [DEBIAN-CVE-2026-64397](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64397.md) | Jul 26, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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