ZDI-26-684: Linux Kernel KSMBD Query Directory Request Race Condition Remote Code Execution Vulnerability
ZDI discloses CVE-2026-64397, a CVSS 9.0 unauthenticated remote code execution race condition in Linux Kernel KSMBD.
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.
ZDI discloses CVE-2026-64397, a CVSS 9.0 unauthenticated remote code execution race condition in Linux Kernel KSMBD.
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