CVE-2025-59828Network attack vector

Code execution via pre-trust Yarn autoloading

Published Sep 24, 2025 · Updated Sep 24, 2025

Code execution in Anthropic Claude Code before 1.0.39 allows remote attackers to run code via Yarn configuration in an untrusted directory. Before showing the directory trust dialog, Claude Code runs yarn --version; Yarn 2+ then loads plugins and yarnPath named by repository-controlled configuration. A user must open the attacker-controlled directory with Yarn 2 or later installed, after which the code runs with that user's privileges; Yarn Classic is unaffected.

CVSS severity7.7
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in Anthropic Claude Code before 1.0.39 allows remote attackers to run code via Yarn configuration in an untrusted directory. Before showing the directory trust dialog, Claude Code runs yarn --version; Yarn 2+ then loads plugins and yarnPath named by repository-controlled configuration. A user must open the attacker-controlled directory with Yarn 2 or later installed, after which the code runs with that user's privileges; Yarn Classic is unaffected.

The record

CVE
CVE-2025-59828
Published
Sep 24, 2025
Updated
Sep 24, 2025
Vendor
Anthropic
Product
Claude Code
Classifications
CWE-829, CWE-862, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2025Record 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=< 1.0.39

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Anthropic · Claude Codeversion=< 1.0.39

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-829Inclusion of Functionality from Untrusted Control Sphere
CWE-862Missing Authorization
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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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