[joss][sec] possible injection and data leakage

[anibalsolon]

Part of: openjournals/joss-reviews#6336

Loading a malicious JSON file can execute code and leak MRI data (or worse). A simple validation for numeric values during loading can prevent such scenario.

{"points":[[100,164,"0\"><script>window.alert('hey jude')</script><br style=\"display: none;\" data-close=\""]],"values":[10]}

[katjaq]

Thank you for the note. We hadn't thought about this as usually the user themselves is the producer of the json file they'll later load. We'll integrate a sanitiser.

[katjaq]

A check for numbers only has been implemented in # 6bdaf8c. Thank you @r03ert0 .