# CVE-2019-10773: Yarn Improper link resolution before file access (Link Following)

> Attackers can create arbitrary symlinks via crafted bin keys, potentially overwriting files and executing code on the host system.

- **Severity:** High 7.8 (`CVSS:3.1/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:** 16 Dec 2019
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-10773, GHSA-5xf4-f2fq-f69j, ROOT-APP-NPM-CVE-2019-10773, SNYK-JS-YARN-537806,, UBUNTU-CVE-2019-10773

## What is CVE-2019-10773?

CVE-2019-10773 is a high-severity path traversal vulnerability in Yarn, published on 16 Dec 2019. 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

In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted "bin" keys. Existing files could be overwritten depending on the current user permission set.

Weakness: CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2019-10773?

2 open source packages ship an affected version, including yarn. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `yarn` | npm | All versions | 1.22.0 |
| `yarn` | npm | All versions | 1.22.0 |

Products: Yarnpkg Yarn.

## How do I fix CVE-2019-10773?

Upgrade yarn to 1.22.0 or later.

## Is CVE-2019-10773 being exploited?

There is no known exploitation of CVE-2019-10773 in the wild and no public exploit code.

## Other vulnerabilities in Yarn

- [CVE-2019-5448](https://insights.sbomify.com/CVE-2019-5448/): Missing Encryption of Sensitive Data in yarn (high 8.1)
- [CVE-2021-4435](https://insights.sbomify.com/CVE-2021-4435/): Yarn: untrusted search path (high 7.7)
- [CVE-2020-8131](https://insights.sbomify.com/CVE-2020-8131/): Path Traversal in Yarn (high 7.5)
- [CVE-2019-15608](https://insights.sbomify.com/CVE-2019-15608/): TOCTOU Race Condition in Yarn (medium 5.9)
- [CVE-2025-8262](https://insights.sbomify.com/CVE-2025-8262/): yarnpkg Yarn hosted-git-resolver.js explodeHostedGitFragment redos (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-10773 and fix it if it is affected.

What it is: CVE-2019-10773 is a high-severity path traversal vulnerability in Yarn, published on 16 Dec 2019. 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-2019-10773 in the wild and no public exploit code.

Affected packages and fixed versions:
- yarn (npm): affected all versions; fixed in 1.22.0
- yarn (npm): affected all versions; fixed in 1.22.0

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-2019-10773/ (Markdown: https://insights.sbomify.com/CVE-2019-10773/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-10773
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-10773
- OSV: https://osv.dev/vulnerability/CVE-2019-10773

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-10773/
Summaries are generated and may contain mistakes; the official description above is the record.