CVE-2020-8131Public exploitNetwork attack vector

Arbitrary file write via unjailed archive symlinks

Published Feb 24, 2020 · Updated Aug 4, 2024

Path traversal in Yarn before 1.22.0 allows remote attackers to write arbitrary files by inducing installation of a malicious package. The tarball fetcher passed attacker-controlled archive link targets to extraction without rebasing them inside the package directory, so crafted symlinks escaped that directory. A user must run yarn install on the package; the write occurs even with --ignore-scripts and can replace files writable by that user's account.

CVSS severity7.5
High
EPSS probability5.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Yarn before 1.22.0 allows remote attackers to write arbitrary files by inducing installation of a malicious package. The tarball fetcher passed attacker-controlled archive link targets to extraction without rebasing them inside the package directory, so crafted symlinks escaped that directory. A user must run yarn install on the package; the write occurs even with --ignore-scripts and can replace files writable by that user's account.

The record

CVE
CVE-2020-8131
Published
Feb 24, 2020
Updated
Aug 4, 2024
Vendor
Yarn
Product
Yarn
Classifications
CWE-22, T1195.001, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Fixed Version: 1.22.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yarn · Yarnversion=Fixed Version: 1.22.0

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
5.1NIST NVDAV:N/AC:H/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1195.001Compromise Software Dependencies and Development Tools
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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