fail2ban: unspecified vulnerability

From the Fedora advisory:

The release notes for fail2ban 0.8.8 [1],[2] indicate:

* [83109bc] IMPORTANT: escape the content of <matches> (if used in custom action files) since its value could contain arbitrary symbols. Thanks for discovery go to the NBS System security team

This could cause issues on the system running fail2ban as it scans log files, depending on what content is matched. There isn't much more detail about this issue than what is described above, so I think it may largely depend on the type of regexp used (what it matches) and the contents of the log file being scanned (whether or not an attacher could insert something that could be used in a malicious way).