{"id":"GHSA-rw54-6826-c8j5","aliases":["CVE-2023-50714"],"title":"yiisoft/yii2-authclient's Oauth2 PKCE implementation is vulnerable","description":"### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nOriginal Report:\n\n> The Oauth2 PKCE implementation is vulnerable in 2 ways:\n> 1. The `authCodeVerifier` should be removed after usage (similar to 'authState')\n> 2. There is a risk for a \"downgrade attack\" if PKCE is being relied on for CSRF protection.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\n2.2.15\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nnot known yet.\n\n### References\n_Are there any links users can visit to find out more?_\n","severity":"medium","score":6.8,"published":"2023-12-18T19:34:20.000Z","modified":"2026-09-10T03:50:09.131Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"yiisoft/yii2-authclient","ranges":[{"events":[{"introduced":"0"},{"fixed":"2.2.15"}],"type":"ECOSYSTEM"}],"versions":["2.0.0","2.0.0-beta","2.0.0-rc","2.0.1","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.1.0","2.1.1","2.1.2","2.1.3","2.1.4","2.1.5","2.1.6","2.1.7","2.1.8","2.2.0","2.2.1","2.2.10","2.2.11","2.2.12","2.2.13","2.2.14","2.2.2","2.2.3","2.2.4","2.2.5","2.2.6","2.2.7","2.2.8","2.2.9"],"fixed":["2.2.15"]}],"references":["https://github.com/yiisoft/yii2-authclient/security/advisories/GHSA-rw54-6826-c8j5","https://nvd.nist.gov/vuln/detail/CVE-2023-50714","https://github.com/yiisoft/yii2-authclient/commit/721ed974bc44137437b0cdc8454e137fff8db213","https://github.com/yiisoft/yii2-authclient","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"],"sources":[{"name":"OSV","id":"GHSA-rw54-6826-c8j5","modified":"2026-09-10T03:50:09.131571556Z","url":"https://osv.dev/vulnerability/GHSA-rw54-6826-c8j5"}],"assessments":[{"source":"OSV","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N","score":6.8}]}