Nope. If there was, virtually every Rails app would be doomed.

There's a sort of intuitive insecurity quotient for things that goes something like C/W_s where C is complexity and W_s is the number of people in the world who would be screwed if something was totally broken.

Encrypted session cookies have, as a design, relatively modest C and very, very high W_s.

JWT has extraordinarily high C and, at present, modest W_s (relative to session cookies).

(They also have a bunch of design flaws that amplify their complexity).

Yep. I was brought on to a project where the JWT secret was a 6 letter band name. It's the hotness newness in the JS community and there's a lot of tutorials out there that show how easy it is to set up without explaining the risks/trade-offs.