Possible XSS vulnerabilities about github-renderer HOT 2 CLOSED

Sorry, I'm an idiot. The files are hosted on raw.github.com, thus eliminating the XSS threat.

from github-renderer.

I believe that XSS is a huge problem with this bookmarklet. Although the JS files might be loaded from raw.github.com, they're still executed in the github.com context.

I forked the repo and edited example.html to provide a proof of concept. Just run the githtml bookmarklet on this page:

https://github.com/dergachev/githtml/blob/master/example.html

Note: my XSS code is fairly harmless, as it just alerts your github username.
But it could have just as easily deleted your github acount, so read it first before using this bookmarklet.

I'm not exactly sure how one could re-architect the bookmarklet to avoid this. Perhaps via iframe src="https://raw.github.com/.../example.html", though I really haven't thought this through.

At the very least, you should warn people very clearly that by running this bookmarklet on an HTML page uploaded to github.com, they're willing to trust it not to steal their github credentials.

(Aside from this, I think this bookmarklet is a really useful idea! I guess you might modify it to work with gists too)

from github-renderer.