What’s Vulnerable › Vulnerabilities

CVE-2023-50708: yii2-authclient vulnerable to possible timing attack on string comparison in OAuth1, OAuth2 and OpenID Connect implementation

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-12-22 · updated 2026-06-17
• Weakness: CWE-203

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 Oauth1/2 `state` and OpenID Connect `nonce` is vulnerable for a `timing attack` since it is compared via regular string comparison (instead of `Yii::$app->getSecurity()->compareString()`). Version 2.2.15 contains a patch for the issue. No known workarounds are available.

Affected products

• yiisoft yii2-authclient: before 2.2.15 — fixed in 2.2.15

How to fix

Upgrade to a fixed version: yiisoft yii2-authclient 2.2.15. Check the vendor advisory for mitigations.

References

• 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
• https://github.com/yiisoft/yii2-authclient/commit/dabddf2154ab7e7703740205a069202554089248
• https://github.com/yiisoft/yii2-authclient/security/advisories/GHSA-w8vh-p74j-x9xp
• 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
• https://github.com/yiisoft/yii2-authclient/commit/dabddf2154ab7e7703740205a069202554089248
• https://github.com/yiisoft/yii2-authclient/security/advisories/GHSA-w8vh-p74j-x9xp

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