In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent NULL dereference in nfsd4_process_cb_update() @ses is initialized to NULL. If __nfsd4_find_backchannel() finds no available backchannel session, setup_callback_client() will try to dereference @ses and segfault.
The product dereferences a pointer that it expects to be valid but is NULL.