CVE-2025-66032
📋 TL;DR
CVE-2025-66032 is a command injection vulnerability in Claude Code that allows bypassing read-only validation to execute arbitrary code. Attackers can exploit this by injecting malicious shell commands through $IFS and short CLI flag parsing errors. Users of Claude Code versions before 1.0.93 are affected.
💻 Affected Systems
- Claude Code
📦 What is this software?
Claude Code by Anthropic
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the host running Claude Code, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Arbitrary code execution within the Claude Code environment, allowing attackers to access sensitive data, modify files, or establish persistence.
If Mitigated
Limited impact if proper input validation and sandboxing are in place, potentially restricting execution to isolated containers.
🎯 Exploit Status
Exploitation requires ability to inject content into Claude Code context. The vulnerability involves shell command parsing errors with $IFS and short flags.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.93
Vendor Advisory: https://github.com/anthropics/claude-code/security/advisories/GHSA-xq4m-mc3c-vvg3
Restart Required: Yes
Instructions:
1. Stop Claude Code service. 2. Update to version 1.0.93 or later using package manager. 3. Restart Claude Code service. 4. Verify version is 1.0.93+.
🔧 Temporary Workarounds
Disable untrusted content
allPrevent users from adding untrusted content to Claude Code context windows
Sandbox execution
linuxRun Claude Code in isolated container or sandboxed environment
docker run --security-opt=no-new-privileges -d anthropics/claude-code
🧯 If You Can't Patch
- Isolate Claude Code instances from sensitive systems and networks
- Implement strict input validation and sanitization for all content entering Claude Code context
🔍 How to Verify
Check if Vulnerable:
Check Claude Code version. If version is less than 1.0.93, system is vulnerable.Check Version:
claude-code --versionVerify Fix Applied:
Confirm version is 1.0.93 or higher and test that shell command injection attempts are properly blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual shell command execution patterns
- Attempts to use $IFS or short flag manipulation
- Unexpected process spawns from Claude Code
Network Indicators:
- Outbound connections from Claude Code to unexpected destinations
- Command and control traffic patterns
SIEM Query:
process_name:"claude-code" AND (command_line:"$IFS" OR command_line:"short_flag_manipulation_patterns")