CVE-2026-46406 PUBLISHED

Claude Code: Insecure Temporary File in /copy Command Enables Response Disclosure and Symlink-Based File Write

Assigner: GitHub_M
Reserved: 13.05.2026 Published: 29.06.2026 Updated: 29.06.2026

Claude Code is an agentic coding tool. From 2.1.59 until 2.1.128, the Claude Code /copy command wrote responses to a hardcoded, predictable path (/tmp/claude/response.md) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user's Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the /copy command. This vulnerability is fixed in 2.1.128.

Metrics

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
CVSS Score: 4.4

Product Status

Vendor anthropics
Product claude-code
Versions
  • Version >= 2.1.59, < 2.1.128 is affected

References

Problem Types

  • CWE-59: Improper Link Resolution Before File Access ('Link Following') CWE
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-377: Insecure Temporary File CWE