CVE-2026-46406

Summary

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.

Affected Software

Weaknesses

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

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://github.com/anthropics/claude-code/security/advisories/GHSA-4vp2-6q8c-pvq2

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