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How the CVE Works:
This vulnerability is a symlink-based permission bypass in Anthropic’s Claude Code. The security mechanism that enforces user-defined deny rules for file access does not properly resolve symbolic links before performing its permission check. When a user has explicitly denied Claude Code access to a specific file, the application would only check the permissions of the direct path being accessed. If an attacker or process creates a symlink pointing to the restricted file, and Claude Code has access to that symlink’s location, the application follows the symlink without re-validating permissions against the final target file. This allows the AI to read and potentially interact with the content of files that should be blocked according to the configured deny rules, effectively circumventing the intended security boundary through a simple file system link.
DailyCVE Form:
Platform: Anthropic Claude Code
Version: Pre-fix versions
Vulnerability: Symlink Permission Bypass
Severity: Low
date: 2025-10-03
Prediction: Patch released 2025-10-03
What Undercode Say:
find /path/to/workspace -type l -ls readlink /path/to/suspected_symlink ls -la /path/to/restricted_file cat /etc/passwd ln -s /etc/passwd ./bypass_link
How Exploit:
Create symlink to denied file
Access through symlink path
Bypass permission deny rules
Read restricted content
Protection from this CVE:
Update Claude Code immediately
Review file deny rules
Audit symlinks in workspace
Implement filesystem monitoring
Impact:
Unauthorized file access
Permission rule bypass
Information disclosure
Security control circumvention
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Sources:
Reported By: github.com
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