# CVE-2018-8171: Security feature bypass vulnerability exists in ASP.NET when the number of incorrect login attempts is not validated

> Attackers can bypass account lockout mechanisms in ASP.NET applications by exploiting a lack of validation for incorrect login attempts.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-vhvh-528q-ff3p

## What is CVE-2018-8171?

CVE-2018-8171 is a high-severity vulnerability in Microsoft ASP.NET, published on 11 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2018-8171?

8 open source packages ship an affected version, including Microsoft.AspNetCore.Identity. It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.AspNetCore.Identity` | NuGet | From 1.0.0 | 1.0.6 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 1.0.0 | 1.0.6 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 1.1.0 | 1.1.6 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 1.1.0 | 1.1.6 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 2.0.0 | 2.0.4 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 2.0.0 | 2.0.4 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 2.1.0 | 2.1.2 |
| `Microsoft.AspNetCore.Identity` | NuGet | From 2.1.0 | 2.1.2 |

Products: Microsoft Asp.net Core, Microsoft Asp.net Model View Controller, Microsoft Asp.net Webpages.

## How do I fix CVE-2018-8171?

Upgrade Microsoft.AspNetCore.Identity to a fixed version for your release line: 1.0.6, 1.1.6, 2.0.4 or 2.1.2.

## Is CVE-2018-8171 being exploited?

There is no known exploitation of CVE-2018-8171 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft ASP.NET

- [CVE-2025-55315](https://insights.sbomify.com/CVE-2025-55315/): ASP.NET Security Feature Bypass Vulnerability (critical 9.9)
- [CVE-2026-88092](https://insights.sbomify.com/CVE-2026-88092/): ASP.NET Core Tampering Vulnerability (critical 9.4)
- [CVE-2026-40372](https://insights.sbomify.com/CVE-2026-40372/): ASP.NET Core Elevation of Privilege Vulnerability (critical 9.1)
- [CVE-2021-43877](https://insights.sbomify.com/CVE-2021-43877/): ASP.NET Core and Visual Studio Elevation of Privilege Vulnerability (high 8.8)
- [CVE-2020-0603](https://insights.sbomify.com/CVE-2020-0603/): Remote code execution in ASP.NET Core (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-8171 and fix it if it is affected.

What it is: CVE-2018-8171 is a high-severity vulnerability in Microsoft ASP.NET, published on 11 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-8171 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.AspNetCore.Identity (NuGet): affected from 1.0.0; fixed in 1.0.6
- Microsoft.AspNetCore.Identity (NuGet): affected from 1.0.0; fixed in 1.0.6
- Microsoft.AspNetCore.Identity (NuGet): affected from 1.1.0; fixed in 1.1.6
- Microsoft.AspNetCore.Identity (NuGet): affected from 1.1.0; fixed in 1.1.6
- Microsoft.AspNetCore.Identity (NuGet): affected from 2.0.0; fixed in 2.0.4
- Microsoft.AspNetCore.Identity (NuGet): affected from 2.0.0; fixed in 2.0.4
- Microsoft.AspNetCore.Identity (NuGet): affected from 2.1.0; fixed in 2.1.2
- Microsoft.AspNetCore.Identity (NuGet): affected from 2.1.0; fixed in 2.1.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-8171/ (Markdown: https://insights.sbomify.com/CVE-2018-8171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-8171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-8171
- OSV: https://osv.dev/vulnerability/CVE-2018-8171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-8171/
Summaries are generated and may contain mistakes; the official description above is the record.