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CVE-2026-21852GHSA-JH7P-QR78-84P7

Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.0.65
4 proofs of concept on GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

Claude Code is an agentic coding tool. Prior to version 2.0.65, vulnerability in Claude Code's project-load flow allowed malicious repositories to exfiltrate data including Anthropic API keys before users confirmed trust. An attacker-controlled repository could include a settings file that sets ANTHROPIC_BASE_URL to an attacker-controlled endpoint and when the repository was opened, Claude Code would read the configuration and immediately issue API requests before showing the trust prompt, potentially leaking the user's API keys. Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to version 2.0.65, which contains a patch, or to the latest version.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated
  4. EPSS reached 10%

    FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

  • anthropics claude-code

    fixed in 2.0.65

  • @anthropic-ai/claude-codenpm

    fixed in 2.0.65

References 5

GitHub · anthropics/claude-code

GitHub · Perufitlife/dotclaude-security

GitHub · TreRB/ai-ide-config-guard

GitHub · abhishek2512mishra/claude-code-security-audit

GitHub · atiilla/CVE-2026-21852-PoC