Impact What kind of vulnerability is it? Who is impacted?

Original Report:

The Oauth2 PKCE implementation is vulnerable in 2 ways: 1. The authCodeVerifier should be removed after usage (similar to 'authState') 2. There is a risk for a "downgrade attack" if PKCE is being relied on for CSRF protection.

Patches Has the problem been patched? What versions should users upgrade to?

2.2.15

Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading?

not known yet.

References Are there any links users can visit to find out more?

Impact What kind of vulnerability is it? Who is impacted?

Original Report:

The Oauth1/2 "state" and OpenID Connect "nonce" is vulnerable for a "timing attack" since it's compared via regular string comparison (instead of Yii::$app->getSecurity()->compareString()).

Affected Code:

1. OAuth 1 "state"

https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth1.php#L158

3. OAuth 2 "state" https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth2.php#L121

4. OpenID Connect "nonce" https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OpenIdConnect.php#L420

Patches Has the problem been patched? What versions should users upgrade to?

TBD: Replace strcmp with Yii::$app->getSecurity()->compareString()).

Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading?

not as far as I see.

References Are there any links users can visit to find out more?