{"id":"CVE-2023-50714","aliases":["GHSA-rw54-6826-c8j5"],"url":"https://o3.security/vulnerability/CVE-2023-50714","summary":"The Oauth2 PKCE implementation is vulnerable","details":"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.","published":"2023-12-22T18:30:03.118Z","modified":"2026-07-15T01:49:02.203816887Z","cvss":{"score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Packagist","name":"yiisoft/yii2-authclient","fixedVersion":"2.2.15"}],"fix":{"url":"https://github.com/yiisoft/yii2-authclient/commit/721ed974bc44137437b0cdc8454e137fff8db213","label":"yiisoft/yii2-authclient@721ed97"},"references":[{"type":"WEB","url":"https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth1.php#L158"},{"type":"WEB","url":"https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OAuth2.php#L121"},{"type":"WEB","url":"https://github.com/yiisoft/yii2-authclient/blob/0d1c3880f4d79e20aa1d77c012650b54e69695ff/src/OpenIdConnect.php#L420"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/50xxx/CVE-2023-50714.json"},{"type":"ADVISORY","url":"https://github.com/yiisoft/yii2-authclient/security/advisories/GHSA-rw54-6826-c8j5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-50714"},{"type":"FIX","url":"https://github.com/yiisoft/yii2-authclient/commit/721ed974bc44137437b0cdc8454e137fff8db213"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:02.203816887Z"}}