@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write
@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write
Medium severity. Affects @anthropic-ai/claude-code >= 2.1.59, < 2.1.128. Upgrade to 2.1.128 or later.
CVE-2026-46406 / GHSA-4vp2-6q8c-pvq2 · severity: medium · npm
Affected
@anthropic-ai/claude-code>= 2.1.59, < 2.1.128 → fixed in 2.1.128
Details
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.
Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.
Claude Code thanks hackerone.com/c_h4ck_0 for reporting this issue.
Source: GHSA-4vp2-6q8c-pvq2 — GitHub Advisory Database (CC-BY-4.0).