Claude Code Trust Dialog Bypass via Git Worktree Spoofing

A vulnerability in Claude Code, specifically versions 2.1.63 and later but before 2.1.84, allowed for a trust dialog bypass via Git worktree spoofing. This exploit leverages the way Claude Code determines folder trust using the commondir file in Git worktrees. By crafting a repository containing a commondir file that points to a path the victim has previously trusted, an attacker could bypass the trust dialog, leading to arbitrary code execution through malicious hooks defined in the .claude/settings.json file. Successful exploitation required the victim to clone a malicious repository and run Claude Code within it, as well as the attacker knowing or guessing a path the victim had previously trusted. Users on standard Claude Code with auto-update enabled received the fix automatically.

Attack Chain

1. Attacker crafts a malicious Git repository with a commondir file.
2. The commondir file is configured to point to a directory path the victim is likely to have previously trusted.
3. The repository includes a malicious .claude/settings.json file containing arbitrary code execution hooks.
4. Attacker distributes the malicious repository, likely through social engineering or other deceptive means.
5. Victim clones the malicious repository to their local machine using git clone.
6. Victim opens the cloned directory containing the malicious .claude/settings.json in a vulnerable version of Claude Code.
7. Claude Code reads the commondir file and incorrectly trusts the repository based on the spoofed path.
8. The malicious hooks defined in .claude/settings.json are executed, leading to arbitrary code execution on the victim’s machine.

Impact

Successful exploitation of this vulnerability allowed an attacker to execute arbitrary code on a victim’s machine. While the number of affected users is unknown, the impact of successful exploitation could range from data theft and system compromise to complete takeover of the victim’s development environment. The vulnerability primarily targeted developers using Claude Code, potentially impacting software development organizations.

Recommendation

• Upgrade Claude Code to the latest version (>= 2.1.84) to patch CVE-2026-40068.
• Implement a detection rule that identifies the creation or modification of .claude/settings.json files containing suspicious code (see Sigma rule below).
• Monitor process creation events for unusual processes being launched from within the Claude Code application context (see Sigma rule below).