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Firefox Smart Window Private URL Exfiltration
Smart Window sets privateData without untrustedInput — attacker titles coerce get_page_content to fetch expanded private tab/history URL tokens.
Summary
Smart Window sets privateData without untrustedInput — attacker titles coerce get_page_content to fetch expanded private tab/history URL tokens. This proof-of-concept is one of 30 folders in the Exploitarium collection. OFFSITE.DARK summarizes the upstream README and PoC design; we did not discover or weaponize this flaw.
Key Findings
| Finding | Detail |
|---|---|
| Product / target | Firefox 152.0.2 x64 (Windows) |
| Primitive | URL token expansion in tool args when privateData=true and untrustedInput=false |
| Impact | Private tab/history URLs (queries, tokens, reset links) leak to attacker HTTP endpoint via hidden fetch. |
Attack Chain
Malicious title in tab/history → get_open_tabs/search_browsing_history → model calls get_page_content with tokenized attacker URL
Mitigation
Update Firefox; disable Smart Window in sensitive profiles; monitor for unexpected outbound fetches from browser.