CVE-2026-21852: anthropic claude_code Insufficiently Protected Credentials

Vulnerability summary

CVE-2026-21852 is a high (CVSS 7.5) Insufficiently Protected Credentials vulnerability in anthropic claude_code. EPSS estimates a 27.50% chance of exploitation in the next 30 days, higher than 98% of scored vulnerabilities.

Timeline

1. 21-01-2026
   PublishedVulnerability first disclosed.
2. 21-01-2026
   Last modifiedVulnerability information updated.

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.

• CWE-522Insufficiently Protected CredentialsThe product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.