O buffer overflow é nada. Olhe para blog de Mark Russinovich para a explicação.
Do these errors indicate a problem? No, they are a standard way for the system to indicate that there’s more information available than can fit into a requester’s output buffer. In other words, the system is telling the caller that if it was to copy all the data requested, it would overflow the buffer. Thus, the error really means that a buffer overflow was avoided, not that one occurred.
The bottom line is that buffer overflow errors in a Filemon trace are not an indication that there's a security problem and are usually not due to bad programming.