What’s Vulnerable › Vulnerabilities
CVE-2026-21852: Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 27.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-01-21 · updated 2026-06-17
- Weakness: CWE-522
Description
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.
Affected products
- anthropics claude-code: before 2.0.65 — fixed in 2.0.65
How to fix
Upgrade to a fixed version: anthropics claude-code 2.0.65. Check the vendor advisory for mitigations.
References
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