Command Validation Bypass Allows Arbitrary Code Execution

High8.7CVE-2025-66032 · Published Dec 3, 2025

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!