In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix UAF in _closefiletableids A use-after-free is possible if one thread destroys the file via _ksmbdclosefd while another thread holds a reference to it. The existing checks on fp->refcount are not sufficient to prevent this. The fix takes ft->lock around the section which removes the file from the file table. This prevents two threads acquiring the same file pointer via _closefiletable_ids, as well as the other functions which retrieve a file from the IDR and which already use this same lock.