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).

Tor Browser through 8.5.3 has an information exposure vulnerability. It allows remote attackers to detect the browser's language via vectors involving an IFRAME element, because text in that language is included in the title attribute of a LINK element for a non-HTML page. This is related to a behavior of Firefox before 68.