As seen in bug 16776 comment 26, mgaadv produced a broken advisory (http://advisories.mageia.org/MGASA-2016-0006.html) when parsing a description with the word "<script>" (http://svnweb.mageia.org/advisories/16776.adv?view=markup). If < and > are valid in yaml, then we probably need to fix the parser. If they are not valid, we should see if advisory uploaders should escape them (and/or avoid them), and if we can print a warning or an error before validating such updates and pushing their advisory. Reproducible: Steps to Reproduce: