# CVE-2020-7666: Arbitrary File Write via Archive Extraction (Zip Slip)

> Attackers can write arbitrary files outside the intended directory via malicious cpio archives, impacting applications using the u-root cpio package.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-mq35-x99r-54fc, MINI-pgqf-hqmc-v84v, MINI-rffj-46fj-52cq, MINI-vr26-q467-h9vh

## What is CVE-2020-7666?

CVE-2020-7666 is a high-severity path traversal vulnerability in github.com/u-root/u-root/pkg/cpio, published on 1 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

This affects all versions of package github.com/u-root/u-root/pkg/cpio. It is vulnerable to leading, non-leading relative path traversal attacks and symlink based (relative and absolute) path traversal attacks in cpio file extraction.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2020-7666?

2 open source packages ship an affected version, including github.com/u-root/u-root/pkg/cpio. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/u-root/u-root/pkg/cpio` | Go | All versions to 7.0.0 | None |
| `github.com/u-root/u-root/pkg/cpio` | Go | All versions to 7.0.0 | None |

Products: U-Root U-Root.

## How do I fix CVE-2020-7666?

Upgrade to a fixed version.

## Is CVE-2020-7666 being exploited?

There is no known exploitation of CVE-2020-7666 in the wild and no public exploit code.

## Other vulnerabilities in github.com/u-root/u-root/pkg/cpio

- [CVE-2020-7665](https://insights.sbomify.com/CVE-2020-7665/): Arbitrary File Write via Archive Extraction (Zip Slip) (high 7.5)
- [CVE-2020-7669](https://insights.sbomify.com/CVE-2020-7669/): Arbitrary File Write via Archive Extraction (Zip Slip) (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-7666 and fix it if it is affected.

What it is: CVE-2020-7666 is a high-severity path traversal vulnerability in github.com/u-root/u-root/pkg/cpio, published on 1 Sep 2020. 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-2020-7666 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/u-root/u-root/pkg/cpio (Go): affected all versions up to 7.0.0; no fix listed
- github.com/u-root/u-root/pkg/cpio (Go): affected all versions up to 7.0.0; no fix listed

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-2020-7666/ (Markdown: https://insights.sbomify.com/CVE-2020-7666/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-7666
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-7666
- OSV: https://osv.dev/vulnerability/CVE-2020-7666

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-7666/
Summaries are generated and may contain mistakes; the official description above is the record.