CVE-2021-39246: Torproject Tor Browser

Medium severity, CVSS 6.1. EPSS: 0.5% chance of exploitation in the next 30 days.

Tor Browser through 10.5.6 and 11.x through 11.0a4 allows a correlation attack that can compromise the privacy of visits to v2 onion addresses. Exact timestamps of these onion-service visits are logged locally, and an attacker might be able to compare them to timestamp data collected by the destination server (or collected by a rogue site within the Tor network).

Affected products

• Torproject Tor Browser: up to and including 10.5.6; version 11.0 only

Published 2021-09-24. Last modified 2026-06-17.