cgi-bin/munin-cgi-graph in Munin 2.x writes data to a log file without sanitizing non-printable characters, which might allow user-assisted remote attackers to inject terminal emulator escape sequences and execute arbitrary commands or delete arbitrary files via a crafted HTTP request.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.