| Package | Affected versions | Patched versions |
|---|---|---|
| claude code | < 1.0.111 | 1.0.111 |
| @anthropic-ai/claude-code | < 1.0.111 | 1.0.111 |
Claude Code contained insufficient URL validation in its trusted domain verification mechanism for WebFetch requests. The application used a startsWith() function to validate trusted domains (e.g., docs.python.org, modelcontextprotocol.io), this could have enabled attackers to register domains like modelcontextprotocol.io.example.com that would pass validation. This could enable automatic requests to attacker-controlled domains without user consent, potentially leading to data exfiltration.
Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.
Thank you to hackerone.com/47sid-praetorian for reporting this issue!
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