How to Check If Your Claude Code Installation Is Affected by CVE-2026-39861 (CVSS 7.7)

📰 Dev.to · Armor1

Check if your Claude Code installation is vulnerable to CVE-2026-39861 and learn how to patch it

intermediate Published 8 May 2026

Action Steps

Check your Claude Code version to see if it's older than 2.1.64
Run a vulnerability scan to detect potential issues
Update Claude Code to version 2.1.64 or later to patch the vulnerability
Verify the patch by re-running the vulnerability scan
Configure your CI/CD pipeline to automatically update dependencies and prevent similar issues in the future

Who Needs to Know This

Developers and DevOps teams using Claude Code should check their installations and apply the patch to prevent potential security breaches

Key Insight

💡 Claude Code versions older than 2.1.64 are vulnerable to a sandbox escape vulnerability (CVE-2026-39861) with a CVSS score of 7.7

Key Takeaways

Check if your Claude Code installation is vulnerable to CVE-2026-39861 and learn how to patch it

CVE-2026-39861 is a sandbox escape in Claude Code, patched in version 2.1.64. The vulnerability...