CVE-2023-50708 is a medium-severity (CVSS 6.1) CWE-203 vulnerability in yiisoft/yii2-authclient. 1 public exploit reference exists, so weaponization risk is real. A fix is available for yiisoft/yii2-authclient — see the affected versions and patch details below.
yii2-authclient vulnerable to possible timing attack on string comparison in OAuth1, OAuth2 and OpenID Connect implementation
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-50708 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
yiisoft/yii2-authclientReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | yiisoft/yii2-authclient | all versions | 2.2.15composer require yiisoft/yii2-authclient:^2.2.15 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yiisoft/yii2-authclient, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yiisoft/yii2-authclient to 2.2.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-50708 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-50708 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-50708. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-50708 in your dependencies?
O3 Security finds CVE-2023-50708 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.