CVE-2026-46406
@anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write
Description
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.
How to fix CVE-2026-46406
To remediate CVE-2026-46406, upgrade the affected package to a fixed version below.
- —upgrade to 2.1.128 or later
Is CVE-2026-46406 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 2.1.59, < 2.1.128
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |