CVE-2025-66032: Claude Code Command Validation Bypass Allows Arbitrary Code Execution

December 3, 2025 (updated December 4, 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 from GMO Flatt Security Inc. for reporting this issue!

References

github.com/advisories/GHSA-xq4m-mc3c-vvg3
github.com/anthropics/claude-code
github.com/anthropics/claude-code/security/advisories/GHSA-xq4m-mc3c-vvg3
nvd.nist.gov/vuln/detail/CVE-2025-66032

Code Behaviors & Features

Detect and mitigate CVE-2025-66032 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →