CVE-2018-15121 — Auth0-ASPNET-Owin
HIGHCVE-2018-15121 is a high-severity (CVSS 8.8) Cross-Site Request Forgery (CSRF) vulnerability in Auth0-ASPNET-Owin. No vendor fix is recorded yet; mitigation options are listed below.
Auth0-ASPNET and Auth0-ASPNET-Owin vulnerable to Cross-Site Request Forgery
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-2018-15121 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 378,156 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
Auth0-ASPNET-Owin.NETauth0-aspnetReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in Auth0 auth0-aspnet and auth0-aspnet-owin. Affected packages do not use or validate the state parameter of the OAuth 2.0 and OpenID Connect protocols. This leaves applications vulnerable to CSRF attacks during authentication and authorization operations.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Auth0-ASPNET-Owin | all versions | No fix |
| .NETNuGet | auth0-aspnet | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Auth0-ASPNET-Owin, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of Auth0-ASPNET-Owin has shipped for CVE-2018-15121 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2018-15121 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-15121. 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-2018-15121 in your dependencies?
O3 Security finds CVE-2018-15121 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.