# CVE-2018-15121: Auth0-ASPNET and Auth0-ASPNET-Owin vulnerable to Cross-Site Request Forgery

> Attackers can perform CSRF attacks during authentication because the library fails to validate the OAuth state parameter, potentially leading to account takeover.

- **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:** No
- **Published:** 29 Aug 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-mmhr-3jr7-qj2p

## What is CVE-2018-15121?

CVE-2018-15121 is a high-severity vulnerability in n/a, published on 29 Aug 2018. 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

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.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2018-15121?

4 open source packages ship an affected version, including Auth0-ASPNET-Owin and auth0-aspnet. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Auth0-ASPNET-Owin` | NuGet | All versions to 2.3.2 | None |
| `Auth0-ASPNET-Owin` | NuGet | All versions to 2.3.2 | None |
| `auth0-aspnet` | NuGet | All versions to 2.1.1 | None |
| `auth0-aspnet` | NuGet | All versions to 2.1.1 | None |

Products: Auth0 Aspnet, Auth0 Aspnet-Owin.

## How do I fix CVE-2018-15121?

No fix has been published for CVE-2018-15121 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-15121 being exploited?

There is no known exploitation of CVE-2018-15121 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-15121 and fix it if it is affected.

What it is: CVE-2018-15121 is a high-severity vulnerability in n/a, published on 29 Aug 2018. 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-2018-15121 in the wild and no public exploit code.

Affected packages and fixed versions:
- Auth0-ASPNET-Owin (NuGet): affected all versions up to 2.3.2; no fix listed
- Auth0-ASPNET-Owin (NuGet): affected all versions up to 2.3.2; no fix listed
- auth0-aspnet (NuGet): affected all versions up to 2.1.1; no fix listed
- auth0-aspnet (NuGet): affected all versions up to 2.1.1; no fix listed

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-2018-15121/ (Markdown: https://insights.sbomify.com/CVE-2018-15121/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-15121
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-15121
- OSV: https://osv.dev/vulnerability/CVE-2018-15121

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From sbomify Insights: https://insights.sbomify.com/CVE-2018-15121/
Summaries are generated and may contain mistakes; the official description above is the record.