CVE-2026-24052: Claude Code has a Domain Validation Bypass which Allows Automatic Requests to Attacker-Controlled Domains
Claude Code contained insufficient URL validation in its trusted domain verification mechanism for WebFetch requests.
What it is
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.
How to check
- Affected: @anthropic-ai/claude-code (npm) < 1.0.111.
- Compare your installed version with the range above (command below).
How to fix
- Upgrade @anthropic-ai/claude-code to 1.0.111 or later.
npm ls @anthropic-ai/claude-code -g # or: claude --versionSources
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