The json-jwt (aka JSON::JWT) gem 1.16.3 for Ruby sometimes allows bypass of identity checks via a sign/encryption confusion attack. For example, JWE can sometimes be used to bypass JSON::JWT.decode.
Exploitability
AV:LAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:H8.4/CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H