Top Risks

• THREAT FEED: extension ID independently confirmed malicious by TPCI chrome-mal-ids — Sinceerly [data-theft] + malext.io malicious_extension_sentry (+2.5, capped).
• Gmail host access allows content script to read full email body text on mail.google.com.
• Free-webmail developer (gmail) with no verified publisher status; low accountability.
• No CSP declared (MV3 default applies but no explicit policy); innerHTML sinks present.
• Privacy policy lacks data retention disclosure; third-party sharing admitted.

Evidence

• gmail_host_access manifest host_permissions includes https://mail.google.com/* — full Gmail page access.
• free_webmail_developer store Developer email menloparkmidnightoil@gmail.com; no verified publisher badge.
• dom_xss_sink crx Two innerHTML sinks in popup.js and content.js; no CSP to mitigate.
• proxy_endpoint manifest sinceerly-proxy.ben-001.workers.dev is a personal Cloudflare Worker; email data routed through it.
• privacy_retention_missing api Privacy policy fetched: scope_extension=true, data_collection=true, retention=false, third_party_sharing=true.
• stripe_endpoints crx js_external_hosts includes api.stripe.com and buy.stripe.com — payment processing expected for SaaS.
• no_cve_findings crx cve_findings_raw empty; no bundled vulnerable libraries detected.
• operator_cluster_clean api sibling_count=0; no related extension cluster detected under same fingerprint.
• threat_feed_membership api Extension ID listed by TPCI chrome-mal-ids — Sinceerly [data-theft] + malext.io malicious_extension_sentry; score 2.77 -> 5.27 (+2.5 cap 2.5).

Permissions Breakdown

• activeTab low Grants access to current tab on user action only; scoped and low-risk.
• storage low Local data persistence; no cross-origin exfil risk on its own.
• https://mail.google.com/* medium Host access to Gmail; can read email content in page context.
• https://sinceerly-proxy.ben-001.workers.dev/* low Developer-controlled proxy; access expected for stated AI function.
• https://api.anthropic.com/* low Direct API call to Anthropic; expected for AI email rewriting feature.

Pillar Scores

Bookkeeping