I'm sure a lot of people and companies got pwned and they aren't going to disclose it. There are chrome extensions that passively polls sites for the vulnerability, and since the vulnerability is so simple to exploit and leaves virtually no trace...

My gut feeling is that we are going to be feeling the consequences of simultaneous enshittification of software, the mounting complexity of our systems, and AI enslopification combine to create far more vulnerabilities in the future. The only defence is to adopt simple systems and software.