(Open Access Management (OpenAM) is an access management solution. Prio ...)

Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, AuthorizationCodeGrantTypeHandler requires a code_verifier only when the realm-wide codeVerifierEnforced setting is enabled, even when an authorization code stores a code_challenge. Because that setting is disabled by default, an attacker who intercepts a PKCE-protected authorization code can omit code_verifier and redeem the code, while an explicitly incorrect verifier is rejected. Public clients are directly affected, and confidential-client exploitation additionally requires client authentication material or another redemption context. This issue is fixed in version 16.1.1.

OpenAM OAuth Authorization Bypass via PKCE Challenge