CVE-2021-44878

Pac4j v5.1 and earlier allows (by default) clients to accept and successfully validate ID Tokens with "none" algorithm (i.e., tokens with no signature) which is not secure and violates the OpenID Core Specification. The "none" algorithm does not require any signature verification when validating the ID tokens, which allows the attacker to bypass the token validation by injecting a malformed ID token using "none" as the value of "alg" key in the header with an empty signature value.

Date published : 2022-01-06

https://github.com/pac4j/pac4j/commit/22b82ffd702a132d9f09da60362fc6264fc281ae

https://openid.net/specs/openid-connect-core-1_0.html#IDToken