2026 Chrome extensions — 287 extensions, 37M installs, browsing data leak
Data compromised
Browsing URLs, search queries, referrers, timestamps, cookies
Technical writeup
Security researcher 'Q Continuum' identified 287 Chrome extensions (37.4M collective installs) leaking browsing history to external parties. Exfiltrated: URLs, search queries, referrers, timestamps, cookies. Recipients included Similarweb, Semrush, Big Star Labs, unknown/Chinese actors. Extensions used encryption/obfuscation. Categories: VPNs, productivity, PDF, shopping. Notable: Pop-up Blocker, Stylish, SimilarWeb, WOT, Video Ad Blocker Plus.
Root cause
Third-party extensions exfiltrating browsing data; data broker partnerships