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.

Urgent
CVSS
9.8
critical
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0048
41st percentile

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

ProductFixed inFixReleased
Linux
linux · Debian 12.15 (bookworm) 6.1.180-1 DEBIAN-CVE-2026-64397 Jul 26, 2026
linux · Debian 13.5 (trixie) 6.12.96-1 DEBIAN-CVE-2026-64397 Jul 26, 2026
linux · Debian 14 7.1.4-1 DEBIAN-CVE-2026-64397 Jul 26, 2026
linux-6.12 · Debian 12.15 (bookworm) 6.12.100-1~deb12u1 DEBIAN-CVE-2026-64397 Jul 26, 2026

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