CVE-2021-39246
lowpriority · track · 24EPSS 0.005 · 41 %ileEUUSEPSS · scored 2026-10-28
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).
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.6–6.1
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (16)
External citations — patches, advisories, analysis.
- https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-111.mdcnnvd
- https://gitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9cnnvd
- https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/434cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-39246cnnvd
- https://sick.codes/sick-2021-111cnnvd
- https://www.privacyaffairs.com/cve-2021-39246-tor-vulnerabilitycnnvd
- https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-111.mdenisa_euvd
- https://gitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9enisa_euvd
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