CVE-2018-8171
HIGHCVE-2018-8171 is a high-severity (CVSS 7.5) Improper Authentication vulnerability in Microsoft.AspNetCore.Identity. O3 Security confirms whether CVE-2018-8171 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Security feature bypass vulnerability exists in ASP.NET when the number of incorrect login attempts is not validated
Blast Radius
Microsoft.AspNetCore.Identity.NETMicrosoft.AspNetCore.Identity.NETMicrosoft.AspNetCore.Identity.NETMicrosoft.AspNetCore.IdentityReal-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
A Security Feature Bypass vulnerability exists in ASP.NET when the number of incorrect login attempts is not validated, aka "ASP.NET Security Feature Bypass Vulnerability." This affects ASP.NET, ASP.NET Core 1.1, ASP.NET Core 1.0, ASP.NET Core 2.0, ASP.NET MVC 5.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.Identity | ≥ 1.0.0&&< 1.0.6 | 1.0.6 |
| .NETNuGet | Microsoft.AspNetCore.Identity | ≥ 1.1.0&&< 1.1.6 | 1.1.6 |
| .NETNuGet | Microsoft.AspNetCore.Identity | ≥ 2.0.0&&< 2.0.4 | 2.0.4 |
| .NETNuGet | Microsoft.AspNetCore.Identity | ≥ 2.1.0&&< 2.1.2 | 2.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.Identity. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Microsoft.AspNetCore.Identity to 1.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-8171 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 pinpoints whether CVE-2018-8171 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2018-8171. 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-2018-8171 in your dependencies?
O3 detects CVE-2018-8171 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.