SB2026043029 - Input validation error in Claude Code

Description

This security bulletin contains information about 1 vulnerability.

1) Input validation error (CVE-ID: CVE-2026-40068)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to improper input validation in the git worktree commondir trust check when determining folder trust for a crafted repository. A remote attacker can craft a repository with a commondir file pointing to a previously trusted path to execute arbitrary code.

Exploitation requires the victim to clone a malicious repository and run Claude Code within it, and for the attacker to know or guess a path the victim had already trusted.

Remediation

Install update from vendor's website.

References

• https://github.com/anthropics/claude-code/security/advisories/GHSA-q5hj-mxqh-vv77
• https://github.com/advisories/GHSA-q5hj-mxqh-vv77