Chinese Characters Inserted Into Dashboard, Website

I am the web manager for a student publication using WordPress for our website. My editor alerted me that writers have been seeing weird artifacts on the website since this morning. Both the website itself and my WordPress Dashboard include Chinese characters inserted at the top (not added by any of the editors). These characters are both in the website title (<title>) and at the header of the page itself and read: 开门 and 输入密码. I’ve tried deactivating and reactivating all of the active plugins, checking the website’s stylesheet and checking the general dashboard settings, but I have found no hint of what is causing this problem. Additionally, the text on the WordPress dashboard is now a neon green (it was black before this problem happened). This green text is also in the body of the website.

I recently updated the site to the newest version of WordPress (5.3 I believe).

I’d appreciate any help on the possible causes and solutions to this problem.