DEBIAN-CVE-2026-64397

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: serialize QUERYDIRECTORY requests per file  smb2querydir() stores a pointer to its stack-allocated private data in the ksmbdfile readdirdata. Concurrent QUERYDIRECTORY requests using the same file handle can overwrite this pointer while an iteratedir() 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, readdirdata 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.