Mar 262 min read
Claude Extension Zero-Click XSS Vulnerability Allows Prompt Injection from Any Website
Key Findings Vulnerability in Anthropic's Claude Chrome extension allowed zero-click prompt injection from any website without user interaction or permission prompts Attack chains two flaws: overly permissive origin allowlist and DOM-based XSS in Arkose Labs CAPTCHA component Successful exploitation could enable data theft, access token compromise, conversation history access, and account takeover Patch deployed December 27, 2025 (version 1.0.41); Arkose Labs fixed XSS compon
