# CVE-2021-3331: Command injection in n/a

> Remote attackers can execute arbitrary programs via crafted URLs in WinSCP, affecting default installations handling sftp links.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 27 Jan 2021
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-rx6x-hw9j-xhm3

## What is CVE-2021-3331?

CVE-2021-3331 is a critical command injection vulnerability in n/a, published on 27 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

WinSCP before 5.17.10 allows remote attackers to execute arbitrary programs when the URL handler encounters a crafted URL that loads session settings. (For example, this is exploitable in a default installation in which WinSCP is the handler for sftp:// URLs.)

## Which versions are affected by CVE-2021-3331?

It affects 1 product.


Products: Winscp Winscp.

## How do I fix CVE-2021-3331?

No fix has been published for CVE-2021-3331 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3331 being exploited?

There is no known exploitation of CVE-2021-3331 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-28864](https://insights.sbomify.com/CVE-2020-28864/): Memory corruption in n/a (critical 9.8)
- [CVE-2007-4909](https://insights.sbomify.com/CVE-2007-4909/): Other in n/a (critical 9.3)
- [CVE-2018-20684](https://insights.sbomify.com/CVE-2018-20684/): Path traversal in n/a (high 7.5)
- [CVE-2006-3015](https://insights.sbomify.com/CVE-2006-3015/): Command injection in n/a (high 7.1)
- [CVE-2014-2735](https://insights.sbomify.com/CVE-2014-2735/): Security feature bypass in n/a (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3331 and fix it if it is affected.

What it is: CVE-2021-3331 is a critical command injection vulnerability in n/a, published on 27 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3331 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-3331/ (Markdown: https://insights.sbomify.com/CVE-2021-3331/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3331
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3331
- OSV: https://osv.dev/vulnerability/CVE-2021-3331

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3331/
Summaries are generated and may contain mistakes; the official description above is the record.