# CVE-2018-1000210: High severity vulnerability that affects YamlDotNet and YamlDotNet.Signed

> Attackers can execute arbitrary code by tricking applications into parsing malicious YAML files using vulnerable YamlDotNet versions.

- **Severity:** High 7.8 (`CVSS:3.0/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 Jul 2018
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-rpch-cqj9-h65r

## What is CVE-2018-1000210?

CVE-2018-1000210 is a high-severity unsafe deserialization vulnerability in n/a, published on 13 Jul 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

YamlDotNet version 4.3.2 and earlier contains a Insecure Direct Object Reference vulnerability in The default behavior of Deserializer.Deserialize() will deserialize user-controlled types in the line "currentType = Type.GetType(nodeEvent.Tag.Substring(1), throwOnError: false);" and blindly instantiates them. that can result in Code execution in the context of the running process. This attack appear to be exploitable via Victim must parse a specially-crafted YAML file. This vulnerability appears to have been fixed in 5.0.0.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2018-1000210?

4 open source packages ship an affected version, including YamlDotNet and YamlDotNet.Signed. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `YamlDotNet` | NuGet | All versions | 5.0.0 |
| `YamlDotNet` | NuGet | All versions | 5.0.0 |
| `YamlDotNet.Signed` | NuGet | All versions | 5.0.0 |
| `YamlDotNet.Signed` | NuGet | All versions | 5.0.0 |

Products: Yamldotnet Project Yamldotnet.

## How do I fix CVE-2018-1000210?

Upgrade YamlDotNet to 5.0.0 or later.

## Is CVE-2018-1000210 being exploited?

There is no known exploitation of CVE-2018-1000210 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-1000210 and fix it if it is affected.

What it is: CVE-2018-1000210 is a high-severity unsafe deserialization vulnerability in n/a, published on 13 Jul 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-1000210 in the wild and no public exploit code.

Affected packages and fixed versions:
- YamlDotNet (NuGet): affected all versions; fixed in 5.0.0
- YamlDotNet (NuGet): affected all versions; fixed in 5.0.0
- YamlDotNet.Signed (NuGet): affected all versions; fixed in 5.0.0
- YamlDotNet.Signed (NuGet): affected all versions; fixed in 5.0.0

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-2018-1000210/ (Markdown: https://insights.sbomify.com/CVE-2018-1000210/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-1000210
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-1000210
- OSV: https://osv.dev/vulnerability/CVE-2018-1000210

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-1000210/
Summaries are generated and may contain mistakes; the official description above is the record.