Drawing attention on this instance so Admins are aware and can address the propagating exploit.

EDIT: Found more info about the patch.

A more thorough recap of the issue.

GitHub PR fixing the bug: https://github.com/LemmyNet/lemmy-ui/pull/1897/files

If your instance has custom emojis defined, this is exploitable everywhere Markdown is available. It is NOT restricted to admins, but can be used to steal an admin’s JWT, which then lets the attacker get into that admin’s account which can then spread the exploit further by putting it somewhere where it’s rendered on every single page and then deface the site.

If your instance doesn’t have any custom emojis, you are safe, the exploit requires custom emojis to trigger the bad code branch.

  • philm
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    1 year ago

    Haha, I came to the same conclusion, but to be fair he’s not from lemmy, he’s just a lost soul in the fediverse (nothing against kbin though) strenuously believing that the devs of lemmy have evil intent and sell us all to “communist china” lol.