GHSA-w8vh-p74j-x9xp is a none-severity (CVSS 0) 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
GHSA-w8vh-p74j-x9xp 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
Impact
What kind of vulnerability is it? Who is impacted?
Original Report:
The Oauth1/2 "state" and OpenID Connect "nonce" is vulnerable for a "timing attack" since it's compared via regular string comparison (instead of
Yii::$app->getSecurity()->compareString()).
Affected Code:
-
OAuth 1 "state"
-
OAuth 2 "state"
-
OpenID Connect "nonce"
Patches
Has the problem been patched? What versions should users upgrade to?
TBD: Replace strcmp with Yii::$app->getSecurity()->compareString()).
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
not as far as I see.
References
Are there any links users can visit to find out more?
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 GHSA-w8vh-p74j-x9xp 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 GHSA-w8vh-p74j-x9xp can be triaged on real exposure rather than presence alone.
Tailored to GHSA-w8vh-p74j-x9xp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-w8vh-p74j-x9xp in your dependencies?
O3 Security finds GHSA-w8vh-p74j-x9xp across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.