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Not in CISA KEV
HIGH severity

CVE-2020-7666 — cpio

HIGHFix: u-root/u-root#1817

CVE-2020-7666 is a high-severity (CVSS 7.5) Path Traversal vulnerability in github.com/u-root/u-root/pkg/cpio. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

github.com/u-root/u-root/pkg/cpio Arbitrary File Write via Archive Extraction (Zip Slip)

Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
1 known
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs75th percentile — riskier than 75% of all scored CVEsHighest risk
0.01%0.68%1.36%2.03%0.5%1.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐹github.com/u-root/u-root/pkg/cpio

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

This affects all versions of package github.com/u-root/u-root/pkg/cpio up to and including 7.0.0. It is vulnerable to leading, non-leading relative path traversal attacks and symlink based (relative and absolute) path traversal attacks in cpio file extraction.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/u-root/u-root/pkg/cpioall versionsNo fix

Affected Products

1 product · 1 configurations
Application
u-rootu-root
all
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

This affects all versions of package github.com/u-root/u-root/pkg/cpio. …

snyk.ioNVDSep 2020

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/u-root/u-root/pkg/cpio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of github.com/u-root/u-root/pkg/cpio for CVE-2020-7666. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

This affects all versions of package github.com/u-root/u-root/pkg/cpio up to and including 7.0.0. It is vulnerable to leading, non-leading relative path traversal attacks and symlink based (relative and absolute) path traversal attacks in cpio file extraction.
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CVE-2020-7666: cpio Path Traversal (High 7.5)