Medium [CVE-2026-46406] @anthropic-ai/claude-code: Claude Code: Information disclosure and file overwrite via insecure temporary file in /copy command
This medium-severity Red Hat Linux advisory covers CVE-2026-46406 affecting OpenShift Lightspeed.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
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.
This allowed a local unprivileged user to read sensitive information from a privileged user's Claude response, potentially containing secrets or credentials. Red Hat rates this Moderate with a CVSS score of 6.8, higher than NIST's 6.1.
The difference is in the confidentiality and integrity metrics. Claude Code responses might contain secrets, API keys, credentials, and code, which is why Red Hat scores confidentiality as High rather than Low.
Affected product named by the advisory: OpenShift Lightspeed.
Is CVE-2026-46406 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-46406 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-46406?
Upgrade to a fixed release named by Red Hat:
- 2.1.128
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
- 2.1.128
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- Update Claude Code to version 2.1.128 or later, which uses randomized, UID-isolated temporary file paths with symlink protection. If updating is not immediately possible, avoid using the /copy command on multi-user systems where untrusted local users have access to /tmp.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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