CVE-2025-65099Network attack vector

Code execution via pre-trust Yarn configuration loading

Published Nov 19, 2025 · Updated Nov 20, 2025

Code injection in Anthropic Claude Code before 1.0.39 allows attackers to execute project-supplied code before directory trust. Claude Code invokes yarn --version before trust approval, allowing project-controlled Yarn plugins or yarnPath code to load and run. Exploitation requires Yarn 3.0 or above and a user to start Claude Code in an untrusted directory; injected code runs with that user's privileges.

CVSS severity7.7
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Anthropic Claude Code before 1.0.39 allows attackers to execute project-supplied code before directory trust. Claude Code invokes yarn --version before trust approval, allowing project-controlled Yarn plugins or yarnPath code to load and run. Exploitation requires Yarn 3.0 or above and a user to start Claude Code in an untrusted directory; injected code runs with that user's privileges.

The record

CVE
CVE-2025-65099
Published
Nov 19, 2025
Updated
Nov 20, 2025
Vendor
Anthropic
Product
Claude Code
Classifications
CWE-94, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 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

7.7GitHub CNACVSS: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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002User Execution: Malicious 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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