CVE-2026-46406
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 · uneditedClaude Code is an agentic coding tool. From 2.1.59 until 2.1.128, the Claude Code /copy command wrote responses to a hardcoded, predictable path (/tmp/claude/response.md) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user's Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the /copy command. This vulnerability is fixed in 2.1.128.
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 confidenceClaude Code versions 2.1.59 through 2.1.128 have a path traversal and information disclosure vulnerability in the /copy command, which writes responses to a hardcoded predictable path (/tmp/claude/response.md) with world-readable permissions (0644) in a world-traversable directory (0755), allowing any local unprivileged user to read potentially sensitive response content or pre-plant symlinks to overwrite attacker-chosen files.
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>= 2.1.58, < 2.1.128CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Claude Code versionRun 'claude --version' or check the binary/package version. Compare against the affected range: 2.1.59 through 2.1.128Affected if Version is >= 2.1.58 and < 2.1.128 (or 2.1.59 through 2.1.127)
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Check if vulnerable output file existsInspect /tmp/claude/response.md with 'ls -la /tmp/claude/response.md'Affected if File exists at the hardcoded path /tmp/claude/response.md
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Verify file permissions are insecureRun 'stat -c '%a' /tmp/claude/response.md' to check the octal permissionsAffected if Permissions are 0644 (world-readable)
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Verify directory permissions allow traversalRun 'stat -c '%a' /tmp/claude/' to check the directory modeAffected if Directory mode is 0755 (world-traversable)
User is affected if Claude Code version is between 2.1.59 and 2.1.128 AND the /tmp/claude/response.md file exists with world-readable permissions in a world-traversable directory.
Generated from the published advisory. Verify against your own configuration.
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 · scoped2.1.128
Upgrade Claude Code to version 2.1.128 or later, which implements proper UID isolation, randomness, and symlink protection for the response file path.
2.1.128
- Upgrade Claude Code to version 2.1.128 or later to remediate this vulnerability
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-46406 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-46406 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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