Information disclosure in Anthropic Claude Code

CVE-2026-46406

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.

EPSS: 0.001 (2.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-46406?
CVE-2026-46406 is a medium-severity vulnerability in Anthropic Claude Code, classified under Improper Link Resolution Before File Access. CVSS score: 6.1/10. Published 2026-06-29.
How severe is CVE-2026-46406?
Medium severity. CVSS v3 base score is 6.1 out of 10.