NWFTPD.nlm before 5.01o in the FTP server in Novell NetWare 5.1 SP3 allows remote authenticated users to cause a denial of service (abend) by sending an RNTO command after a failed RNFR command.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.