Information Disclosure in @anthropic-ai/claude-code (CVE-2026-46406)
Summary
Vulnerability in @anthropic-ai/claude-code (CVE-2026-46406). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.1.128 or later.
Original description
The description as published by the source.
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: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-46406 has been found in @anthropic-ai/claude-code.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade @anthropic-ai/claude-code to 2.1.128 or later.
If unsure, ask your IT team or search "@anthropic-ai/claude-code CVE-2026-46406" on the vendor's site.
CVE-2026-46406 (@anthropic-ai/claude-code) — CWE-200 / CVSS v3 6.1
Attack vector: local
Patched: 2.1.128 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in @anthropic-ai/claude-code.
Check the vendor advisory for the affected versions of @anthropic-ai/claude-code.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 2.1.128.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@anthropic-ai/claude-code' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r '@anthropic-ai/claude-code' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
@anthropic-ai/claude-codeを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @anthropic-ai/claude-code to 2.1.128ステージング環境で 2.1.128 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- package github.com
- web github.com
- web github.com