yiisoft/yii2-authclient's Oauth2 PKCE implementation is vulnerable

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?