Description

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.

Classification

CVE ID: CVE-2023-50714

CVSS Base Severity: MEDIUM

CVSS Base Score: 6.8

Affected Products

Vendor: yiisoft

Product: yii2-authclient

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.16% (probability of being exploited)

EPSS Percentile: 53.67% (scored less or equal to compared to others)

EPSS Date: 2025-02-03 (when was this score calculated)

References

https://github.com/yiisoft/yii2-authclient/security/advisories/GHSA-rw54-6826-c8j5
https://github.com/yiisoft/yii2-authclient/commit/721ed974bc44137437b0cdc8454e137fff8db213
https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth1.php#L158
https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth2.php#L121
https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OpenIdConnect.php#L420

Timeline