# CVE-2017-11879: Open redirect in ASP.NET Core

> Attackers can steal session cookies or tokens via crafted URLs, potentially leading to account takeover in ASP.NET Core applications.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 15 Nov 2017
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-3wcj-rg8q-9cqv

## What is CVE-2017-11879?

CVE-2017-11879 is a high-severity vulnerability in Microsoft Corporation ASP.NET Core, published on 15 Nov 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

ASP.NET Core 2.0 allows an attacker to steal log-in session information such as cookies or authentication tokens via a specially crafted URL aka "ASP.NET Core Elevation Of Privilege Vulnerability".

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2017-11879?

4 open source packages ship an affected version, including Microsoft.AspNetCore.All and Microsoft.AspNetCore.Mvc.Core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.AspNetCore.All` | NuGet | From 2.0.0 | 2.0.3 |
| `Microsoft.AspNetCore.All` | NuGet | From 2.0.0 | 2.0.3 |
| `Microsoft.AspNetCore.Mvc.Core` | NuGet | From 2.0.0 | 2.0.1 |
| `Microsoft.AspNetCore.Mvc.Core` | NuGet | From 2.0.0 | 2.0.1 |

Products: Microsoft Asp.net Core.

## How do I fix CVE-2017-11879?

Upgrade Microsoft.AspNetCore.All to 2.0.3 or later.

## Is CVE-2017-11879 being exploited?

There is no known exploitation of CVE-2017-11879 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Corporation ASP.NET Core

- [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-2017-11879 and fix it if it is affected.

What it is: CVE-2017-11879 is a high-severity vulnerability in Microsoft Corporation ASP.NET Core, published on 15 Nov 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2017-11879 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.AspNetCore.All (NuGet): affected from 2.0.0; fixed in 2.0.3
- Microsoft.AspNetCore.All (NuGet): affected from 2.0.0; fixed in 2.0.3
- Microsoft.AspNetCore.Mvc.Core (NuGet): affected from 2.0.0; fixed in 2.0.1
- Microsoft.AspNetCore.Mvc.Core (NuGet): affected from 2.0.0; fixed in 2.0.1

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-2017-11879/ (Markdown: https://insights.sbomify.com/CVE-2017-11879/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-11879
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-11879
- OSV: https://osv.dev/vulnerability/CVE-2017-11879

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-11879/
Summaries are generated and may contain mistakes; the official description above is the record.