yii2-authclient is an extension that adds OpenID, OAuth, OAuth2 and OpenId Connect consumers for the Yii framework 2.0. In yii2-authclient prior to version 2.2.15, the Oauth2 PKCE implementation is vulnerable in 2 ways. First, the authCodeVerifier
should be removed after usage (similar to authState
). Second, there is a risk for a downgrade attack
if PKCE is being relied on for CSRF protection. Version 2.2.15 contains a patch for the issue. No known workarounds are available.
github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth1.php#L158
github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth2.php#L121
github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OpenIdConnect.php#L420
github.com/yiisoft/yii2-authclient/commit/721ed974bc44137437b0cdc8454e137fff8db213
github.com/yiisoft/yii2-authclient/security/advisories/GHSA-rw54-6826-c8j5