CVE-2025-66032

The record

Due to errors in parsing shell commands related to $IFS and short CLI flags, it was possible to bypass the Claude Code read-only validation and trigger arbitrary code execution. Reliably exploiting this requires the ability to add untrusted content into a Claude Code context window. Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version. Thank you to [RyotaK](hxxps://ryotak.net) from [GMO Flatt Security Inc.](hxxps://flatt.tech/en/) for reporting this issue!

Affected packages

Related vulnerabilities

• GHSA-xq4m-mc3c-vvg3 Claude Code Command Validation Bypass Allows Arbitrary Code Execution Same vulnerability
• CVE-2026-54316 Claude Code is an agentic coding tool. Also affects @anthropic-ai/claude-code
• GHSA-fg94-h982-f3mm Claude Code: Out-of-Band Data Exfiltration via Pre-Approved HuggingFace Domain in WebFetch Also affects @anthropic-ai/claude-code
• CVE-2026-40068 In versions 2.1.63 through 2.1.83 of Claude Code, the folder trust determination logic… Also affects @anthropic-ai/claude-code
• GHSA-q5hj-mxqh-vv77 Claude Code: Trust Dialog Bypass via Git Worktree Spoofing Allows Arbitrary Code Execution Also affects @anthropic-ai/claude-code
• GHSA-vp62-r36r-9xqp Claude Code: Sandbox Escape via Symlink Following Allows Arbitrary File Write Outside… Also affects @anthropic-ai/claude-code
• CVE-2026-39861 Claude Code is an agentic coding tool. Also affects @anthropic-ai/claude-code
• GHSA-5cwg-9f6j-9jvx Claude Code: Insecure System-Wide Configuration Loading Enables Local Privilege… Also affects @anthropic-ai/claude-code