User-defined functions in MySQL allow a user in the database to call binary libraries on the operating system. Creating a user-defined function requires insert privileges on the mysql.func table. The UDF creation functions attempt to filter out directory traversal characters, restricting access to libraries only in system and MySQL directories. The problem exists in the fact that MySQL only uses the forward slash (/) as a path separator. Windows machines use the backslash () character to separate directories in paths. This allows an attacker to bypass directory traversal checks and include arbitrary files.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/39186/2005-001.txt
Source: https://packetstormsecurity.com/files/39186/Trustix-Secure-Linux-Security-Advisory-2005.1.html