Insecure Temporary File in Claude Code - CVE-2026-46406
Published: June 30, 2026
Vulnerability identifier: #VU135960
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-46406
CWE-ID: CWE-377
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Anthropic
Affected software:
Claude Code
Claude Code
Detailed vulnerability description
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to insecure temporary file usage in the /copy command when writing response content to a predictable temporary file path. A local user can read the world-readable temporary file to disclose sensitive information.
Exploitation requires a privileged user on the same system to run the /copy command.
How to mitigate CVE-2026-46406
Install security update from vendor's website.