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Claude CodeApplication · Anthropic

CVE-2026-55607

HIGH · 8.8 CVSS v3.1 Published 2026-06-29
Fix available
A fix is available. Upgrade to 2.1.163 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges 7 weeks old

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. From 2.1.38 until 2.1.163, Claude Code's worktree handling allowed creation of worktrees named ".git" and navigation to worktrees outside the sandbox context, enabling git directory confusion attacks. By exploiting symlink manipulation and git fsmonitor execution during worktree operations, an attacker could overwrite files in the user's home directory (such as .zshenv), leading to code execution outside of seatbelt sandbox restrictions. Reliably exploiting this required the user to clone a malicious repository containing prompt injection content and run Claude Code against it. This vulnerability is fixed in 2.1.163.

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 versions 2.1.38-2.1.163 contained a sandbox escape vulnerability in worktree handling that allowed creation of worktrees named '.git' and navigation outside the sandbox context via symlink manipulation. Attackers could exploit git fsmonitor execution during worktree operations to overwrite files like .zshenv in the user's home directory, achieving code execution outside seatbelt restrictions when users cloned and ran Claude Code against malicious repositories.

MitigationUpgrade Claude Code to version 2.1.163 or later. Avoid cloning or running Claude Code against untrusted repositories.

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:>= 2.1.38, < 2.1.163

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 installed Claude Code version
    Run 'claude --version' or check the application's About/info panel to identify the exact version number
    Affected if The version is 2.1.38 through 2.1.163 inclusive
  2. Verify worktree operations have occurred
    Check for any worktree-related directories or git operations: look for .git worktree refs or check git worktree list output in any repositories you have worked with
    Affected if Worktrees were created or manipulated, particularly with names like '.git' or via symlinks
  3. Inspect home directory for unauthorized modifications
    Review .zshenv, .bashrc, .profile, and other shell initialization files in your home directory for unexpected additions or modifications
    Affected if These files contain suspicious content you did not add, especially if they execute commands from unexpected locations
  4. Check for suspicious worktree directories
    Look for worktree directories named '.git' or directories containing symlinks that point outside expected repository boundaries
    Affected if Such directories or symlinks exist in your working repositories

You are affected if Claude Code version 2.1.38-2.1.163 is installed AND you have cloned or run Claude Code against untrusted repositories where worktree operations occurred.

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 2.1.163 or later
Fixed in 2.1.163
Interim mitigation

Upgrade Claude Code to version 2.1.163 or later. Avoid cloning or running Claude Code against untrusted repositories.

Recommended fix High confidence

2.1.163

  1. Check current Claude Code version by running: claude --version
  2. Upgrade Claude Code to version 2.1.163 or later by downloading the latest release from the official Anthropic Claude Code releases page
  3. Verify the upgrade was successful by running: claude --version

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-2026-55607 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