OAuth2 is a Ruby wrapper for the OAuth 2.0 and 2.1 authorization frameworks, including OpenID Connect (OIDC). From 0.4.0 to 2.0.21, a protocol-relative redirect Location returned to OAuth2::Client#request overrides the request authority, so the bearer Authorization header is sent to an attacker-controlled host, leaking the credential. This issue is fixed in version 2.0.22.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:HI:NA:N8.6/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:NInformation Disclosure
Input Validation