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Claude CodeApplication · Anthropic

CVE-2025-65099

CRITICAL · 9.8 CVSS v3.1 Published 2025-11-19
Fix available
A fix is available. Upgrade to 1.0.39 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Claude Code is an agentic coding tool. Prior to version 1.0.39, when running on a machine with Yarn 3.0 or above, Claude Code could have been tricked to execute code contained in a project via yarn plugins before the user accepted the startup trust dialog. Exploiting this would have required a user to start Claude Code in an untrusted directory and to be using Yarn 3.0 or above. This issue has been patched in version 1.0.39.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Claude Code before version 1.0.39 could execute arbitrary code via Yarn 3.0+ plugins before the startup trust dialog was displayed. An attacker could place malicious yarn plugins in an untrusted project directory, and when a user launched Claude Code in that directory with Yarn 3.0+, the plugins would execute code without waiting for user consent via the trust dialog.

MitigationUpgrade Claude Code to version 1.0.39 or later. Avoid launching Claude Code from untrusted directories when using Yarn 3.0+.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Claude CodeApplication
Affected:< 1.0.39

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Claude Code installed version
    Run `claude --version` or check the installed Claude Code binary version
    Affected if Version is lower than 1.0.39 (e.g., 1.0.38, 1.0.37, etc.)
  2. Verify Yarn 3.0+ is installed
    Run `yarn --version` to determine the Yarn version. For Yarn 3.x (Berry), check for a `.yarnrc.yml` file in the project or home directory
    Affected if Yarn version shows 3.0 or higher, or a Yarn 3.x configuration file exists in the environment
  3. Confirm Yarn plugins can load at startup
    Check if Yarn is configured to auto-load plugins from `node_modules/.yarn/plugins` or from the global Yarn plugin directory. Inspect the Yarn configuration with `yarn plugin list`
    Affected if Yarn plugins are enabled and Yarn is in the system PATH when Claude Code starts
  4. Determine if Claude Code runs from untrusted directories
    Identify the working directory from which Claude Code is typically invoked. Check if it operates in directories that may contain untrusted code or package.json files
    Affected if Claude Code is invoked from directories outside the user's trusted code base, or from directories containing untrusted package.json files

You are affected if Claude Code version is below 1.0.39 AND Yarn 3.0+ is installed and accessible in the environment where Claude Code runs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.0.39 or later
Fixed in 1.0.39
Interim mitigation

Upgrade Claude Code to version 1.0.39 or later. Avoid launching Claude Code from untrusted directories when using Yarn 3.0+.

Recommended fix High confidence

Claude Code 1.0.39

  1. Check current Claude Code version using `claude --version` or the application UI
  2. Upgrade Claude Code to version 1.0.39 or latest available version
  3. Verify the upgrade was successful by checking the version again
  4. If using Yarn 3.0+, ensure you only open Claude Code in trusted project directories

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Claude Code Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-65099 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data