# CVE-2018-20251: Path traversal in WinRAR

> Attackers can create arbitrary empty files and folders outside the intended extraction directory via crafted ACE archives in WinRAR.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N`)
- **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:** No
- **Published:** 5 Feb 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-9p46-rmhc-6xcf

## What is CVE-2018-20251?

CVE-2018-20251 is a medium-severity path traversal vulnerability in Check Point Software Technologies Ltd. WinRAR, published on 5 Feb 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 WinRAR versions prior to and including 5.61, there is path traversal vulnerability when crafting the filename field of the ACE format. The UNACE module (UNACEV2.dll) creates files and folders as written in the filename field even when WinRAR validator noticed the traversal attempt and requestd to abort the extraction process. the operation is cancelled only after the folders and files were created but prior to them being written, therefore allowing the attacker to create empty files and folders everywhere in the file system.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2018-20251?

It affects 1 product.


Products: Rarlab Winrar.

## How do I fix CVE-2018-20251?

No fix has been published for CVE-2018-20251 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-20251 being exploited?

There is no known exploitation of CVE-2018-20251 in the wild and no public exploit code.

## Other vulnerabilities in Check Point Software Technologies Ltd. WinRAR

- [CVE-2025-6218](https://insights.sbomify.com/CVE-2025-6218/): RARLAB WinRAR Path Traversal (high 7.8, exploited in the wild)
- [CVE-2023-38831](https://insights.sbomify.com/CVE-2023-38831/): RARLAB WinRAR Code Execution (high 7.8, exploited in the wild)
- [CVE-2018-20250](https://insights.sbomify.com/CVE-2018-20250/): WinRAR Absolute Path Traversal (high 7.8, exploited in the wild)
- [CVE-2008-7144](https://insights.sbomify.com/CVE-2008-7144/): Memory corruption in n/a (critical 10.0)
- [CVE-2004-1254](https://insights.sbomify.com/CVE-2004-1254/): Integer overflow in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20251 and fix it if it is affected.

What it is: CVE-2018-20251 is a medium-severity path traversal vulnerability in Check Point Software Technologies Ltd. WinRAR, published on 5 Feb 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-2018-20251 in the wild and no public exploit code.

Affected product: Check Point Software Technologies Ltd. WinRAR. 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-2018-20251/ (Markdown: https://insights.sbomify.com/CVE-2018-20251/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20251
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20251
- OSV: https://osv.dev/vulnerability/CVE-2018-20251

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From sbomify Insights: https://insights.sbomify.com/CVE-2018-20251/
Summaries are generated and may contain mistakes; the official description above is the record.