# CVE-2017-11770: Improper Certificate Validation

> An unauthenticated attacker can cause a denial of service in .NET Core web applications by sending malformed certificate data.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Nov 2017
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-7mfr-774f-w5r9

## What is CVE-2017-11770?

CVE-2017-11770 is a high-severity denial of service vulnerability in Microsoft Corporation .NET Core, published on 15 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

.NET Core 1.0, 1.1, and 2.0 allow an unauthenticated attacker to remotely cause a denial of service attack against a .NET Core web application by improperly parsing certificate data. A denial of service vulnerability exists when .NET Core improperly handles parsing certificate data, aka ".NET CORE Denial Of Service Vulnerability".

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2017-11770?

4 open source packages ship an affected version, including Microsoft.NETCore.App and System.Security.Cryptography.X509Certificates. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.NETCore.App` | NuGet | From 1.0.0 | 2.0.3 |
| `Microsoft.NETCore.App` | NuGet | From 1.0.0 | 2.0.3 |
| `System.Security.Cryptography.X509Certificates` | NuGet | From 4.0.0 | 4.1.2 |
| `System.Security.Cryptography.X509Certificates` | NuGet | From 4.0.0 | 4.1.2 |

Products: Microsoft Aspnetcore.

## How do I fix CVE-2017-11770?

Upgrade Microsoft.NETCore.App to 2.0.3 or later.

## Is CVE-2017-11770 being exploited?

There is no known exploitation of CVE-2017-11770 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Corporation .NET Core

- [CVE-2017-11883](https://insights.sbomify.com/CVE-2017-11883/): Denial of service in ASP.NET Core (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-11770 and fix it if it is affected.

What it is: CVE-2017-11770 is a high-severity denial of service vulnerability in Microsoft Corporation .NET Core, published on 15 Nov 2017. 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-2017-11770 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.NETCore.App (NuGet): affected from 1.0.0; fixed in 2.0.3
- Microsoft.NETCore.App (NuGet): affected from 1.0.0; fixed in 2.0.3
- System.Security.Cryptography.X509Certificates (NuGet): affected from 4.0.0; fixed in 4.1.2
- System.Security.Cryptography.X509Certificates (NuGet): affected from 4.0.0; fixed in 4.1.2

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-2017-11770/ (Markdown: https://insights.sbomify.com/CVE-2017-11770/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-11770
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-11770
- OSV: https://osv.dev/vulnerability/CVE-2017-11770

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-11770/
Summaries are generated and may contain mistakes; the official description above is the record.