Many Linux distributions ship with the 'less' command automagically interfaced to 'lesspipe'-type scripts, usually invoked via LESSOPEN. This is certainly the case for CentOS and Ubuntu. Unfortunately, many of these scripts appear to call a rather large number of third-party tools that likely have not been designed with malicious inputs in mind. On CentOS, lesspipe appears to include things such as groff + troff + grotty, man, and cpio.