alt Hacker NewsI should have known this exists, yet I didn't. Thanks for pointing it out.
This seems to be a direct link to a web form to report (in English): https://eservices.traficom.fi/ContactForms/form/haavoittuvuu...
In particular, note that all the fields asking for personal information disappear if you select "Yes" in "I am submitting an anonymous tip" field.
Just to play devil's advocate, couldn't sending zero-day exploits to a foreign nation's intelligence service potentially cause the sender significantly more trouble.