CVE-2026-6770: Firefox Flaw Enables Fingerprinting and Deanonymization of Tor Browser Users

CVE-2026-6770, a Firefox vulnerability, allows attackers to fingerprint Tor Browser users, potentially deanonymizing individuals who rely on Tor for privacy. The flaw has been patched in Firefox 150 and Tor Browser 15.0.10.

Tor users including journalists, activists, and people operating in authoritarian environments face the highest risk from this vulnerability, as it directly undermines the anonymity guarantee that Tor is designed to provide. Tor Browser is based on Firefox ESR; users should update to Tor Browser 15.0.10 or Firefox 150 immediately.