# CVE-2021-41641: Link Following in Deno

> Attackers can bypass file sandbox restrictions via symbolic links to access or modify arbitrary directories when specific write permissions are granted.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jun 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-67hm-27mx-9cg7, JLSEC-2026-99

## What is CVE-2021-41641?

CVE-2021-41641 is a high-severity path traversal vulnerability in n/a, published on 12 Jun 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Deno <=1.14.0 file sandbox does not handle symbolic links correctly. When running Deno with specific write access, the Deno.symlink method can be used to gain access to any directory.

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

## Which versions are affected by CVE-2021-41641?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `deno` | crates.io | All versions | 1.16.0 |
| `deno` | crates.io | All versions | 1.16.0 |

Products: Deno Deno.

## How do I fix CVE-2021-41641?

Upgrade deno to 1.16.0 or later.

## Is CVE-2021-41641 being exploited?

There is no known exploitation of CVE-2021-41641 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-28445](https://insights.sbomify.com/CVE-2023-28445/): Deno improperly handles resizable ArrayBuffer (critical 10.0)
- [CVE-2022-24783](https://insights.sbomify.com/CVE-2022-24783/): Sandbox bypass leading to arbitrary code execution in Deno (critical 10.0)
- [CVE-2021-32619](https://insights.sbomify.com/CVE-2021-32619/): Static imports inside dynamically imported modules do not adhere to permission checks (critical 9.8)
- [CVE-2026-22863](https://insights.sbomify.com/CVE-2026-22863/): Deno node:crypto doesn't finalize cipher (critical 9.2)
- [CVE-2024-27936](https://insights.sbomify.com/CVE-2024-27936/): Deno interactive permission prompt spoofing via improper ANSI stripping (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41641 and fix it if it is affected.

What it is: CVE-2021-41641 is a high-severity path traversal vulnerability in n/a, published on 12 Jun 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-41641 in the wild and no public exploit code.

Affected packages and fixed versions:
- deno (crates.io): affected all versions; fixed in 1.16.0
- deno (crates.io): affected all versions; fixed in 1.16.0

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-2021-41641/ (Markdown: https://insights.sbomify.com/CVE-2021-41641/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41641
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41641
- OSV: https://osv.dev/vulnerability/CVE-2021-41641

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41641/
Summaries are generated and may contain mistakes; the official description above is the record.