Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · Low · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-200.
Summary
Claude 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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| anthropics | claude-code | 2.1.59 to before 2.1.128 | 2.1.128 | Patch available | CNA |
| — | @anthropic-ai/claude-code (npm) | 2.1.59 to before 2.1.128 | 2.1.128 | Patch available | GHSA-4vp2-6q8c-pvq2 |
- claude-code Vendoranthropics Affected 2.1.59 to before 2.1.128 Fixed in 2.1.128 Patch available CNA
- @anthropic-ai/claude-code (npm) Vendor— Affected 2.1.59 to before 2.1.128 Fixed in 2.1.128 Patch available GHSA-4vp2-6q8c-pvq2
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:anthropic:claude_code:*:*:*:*:*:node.js:*:* | 2.1.58 to before 2.1.128 | Vulnerable | anthropics |
- cpe:2.3:a:anthropic:claude_code:*:*:*:*:*:node.js:*:* Versions 2.1.58 to before 2.1.128 Vulnerable ·anthropics
Remediation
- Fix · CNA claude-code (anthropics) Fixed in 2.1.128
- Fix · GHSA-4vp2-6q8c-pvq2 @anthropic-ai/claude-code (npm) Fixed in 2.1.128 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat OpenShift Dev Spaces
Timeline
- 2026-10-02 Threatist record created from CVE-2026-46406
- 2026-10-03 Alias added: GHSA-4vp2-6q8c-pvq2
References
More anthropics Claude Code vulnerabilities
- TI-2025-40558 Claude Code Command Validation Bypass Allows Arbitrary Code Execution CVSS 4.0HIGH 8.7
- TI-2025-36683 Claude Code vulnerable to arbitrary code execution caused by maliciously configured git email CVSS 4.0HIGH 8.7
- TI-2025-37066 Claude Code's startup trust dialog could lead to Command Execution attack CVSS 4.0HIGH 8.7
- TI-2026-17554 Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation CVSS 4.0MEDIUM 5.3
- TI-2025-40093 @anthropic-ai/claude-code has Sed Command Validation Bypass that Allows Arbitrary File Writes CVSS 4.0HIGH 8.7
- TI-2025-36422 Claude Code rg command had Command Injection that allowed bypass of user approval prompt for command execution CVSS 4.0HIGH 8.7
Sources
- CVE-2026-46406 · CVE Program
- CVE-2026-46406 · NVD
- FIRST EPSS
- GHSA-4vp2-6q8c-pvq2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-46406 · Red Hat security data · CC BY 4.0
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