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GICodeWarrior ◴[] No.43519636[source]
The "How to use a Python variable in an external Javascript (Django)" examples are likely vulnerable to an XSS attack, when the variable contains user supplied content.

It's important to output-encode for the correct context. By default, Django encodes template variables for an HTML context, which can allow XSS when output inside a script tag or as a JavaScript file.

replies(2): >>43522190 #>>43522535 #
gynvael ◴[] No.43522190[source]
Thanks! I'll pass this to the author.

Out of curiosity I've started looking in Django docs (I'm more of a flask person myself), and they seems to confirm what you're saying. More to the point, the `strings` are the main issue. The default autoescape actually encodes ' and " as HTML entities, but doesn't encode a backslash, so leaving a \ at end of a ' or " string would escape the string ending - this would be exploitable if the attacker controls two strings of the same "type' in a row.

I guess this is the proper way to do it: https://docs.djangoproject.com/en/5.1/ref/templates/builtins...

replies(2): >>43524059 #>>43526125 #
1. Kwpolska ◴[] No.43524059[source]
All JSON serializers worth their salt can serialize a single string to JSON, so the simplest way is to do json.dumps(the_string) and mark the string as safe so that it doesn't get escaped twice.
replies(1): >>43526014 #
2. GICodeWarrior ◴[] No.43526014[source]
Simple JSON encoding alone is not sufficient if you put the output into a <script> tag.

<script>const user_input = "</script><script>alert(1)//"; ...