(Another) non-persistent XSS attack on Codeforces
Try clicking this link (the domain is codeforces.com)
I notice that any quotation mark in the title will make the part after it disappear.
UPD: The bug is fixed now, however there's another (see the comment below)
Round 946 Div 3 Solution Discussion (with myself)
Codeforces Round 946 Solution Discussion