(URGENT) Lemmy has an XSS vulnerability in the sidebar

https://sh.itjust.works/post/923025

(URGENT) Lemmy has an XSS vulnerability in the tagline, the sidebar and in the legal information field - sh.itjust.works

# DO NOT OPEN THE ā€œLEGALā€ PAGE — lemmy.world is a victim of an XSS attack right now and the hacker simply injected a JavaScript redirection into the sidebar. It appears the Lemmy backend does not escape HTML in the main sidebar. Not sure if this is also true for community sidebars. [https://sh.itjust.works/pictrs/image/707c0f16-3d5c-4888-b865-34228d968ee6.png] EDIT: the exploit is also in the tagline that appears on top of the main feed for status updates, like the following one for SDF Chatter: [https://sh.itjust.works/pictrs/image/2dc8838f-4611-4b62-92d2-ab45d7b1c560.png] [https://sh.itjust.works/pictrs/image/9195ec9c-166e-4190-a991-26d218089602.png] EDIT 2: The legal information field also has that exploit, so that when you go to the ā€œLegalā€ page it shows the HTML unescaped, but fortunately (for now) he’s using double-quotes. "legal_information":" ![\" onload=\"if(localStorage.getItem(`h`) != `true`){document.body.innerHTML = `\u003Ch1\u003ESite has been seized by Reddit for copyright infringment\u003C\u002Fh1\u003E`; setTimeout(() =\u003E {window.location.href = `https:\u002F\u002Flemmy.world\u002Fpictrs\u002Fimage\u002F7aa772b7-9416-45d1-805b-36ec21be9f66.mp4`}, 10000)}\"](https:\u002F\u002Flemmy.world\u002Fpictrs\u002Fimage\u002F66ca36df-4ada-47b3-9169-01870d8fb0ac.png \"lw\")

Not sanitizing user input is plain stupid. There is no excuse. Ever.
Let us see you make a better lemmy then
They probably don’t have one, but that doesn’t change the fact that not sanitizing user-input is still insane.

Mistakes happen. This is one of the most common vulnerabilities in the software world. Again, it’s easy to say it’s insane when you aren’t the one making it. I don’t see you making anything half as good and without mistakes.

Constructive criticism is okay, but this isn’t it. Sounds very entitled.