CVE-2021-39246
First published: Fri Sep 24 2021(Updated: )
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).
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Torproject Tor Browser | <=10.5.6 | |
| Torproject Tor Browser | =11.0-alpha2 | |
| Torproject Tor Browser | =11.0-alpha4 | |
| Apple macOS | ||
| Linux Linux kernel | ||
| Microsoft Windows |
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Reference Links
- https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-111.md
- https://gitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9
- https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/434
- https://sick.codes/sick-2021-111
- https://www.privacyaffairs.com/cve-2021-39246-tor-vulnerability
Frequently Asked Questions
What is CVE-2021-39246?
CVE-2021-39246 is a vulnerability in Tor Browser versions 10.5.6 and 11.x through 11.0a4 that allows a correlation attack compromising the privacy of visits to v2 onion addresses.
How does CVE-2021-39246 affect Tor Browser?
CVE-2021-39246 affects Tor Browser versions 10.5.6 and 11.x through 11.0a4 by enabling a correlation attack that compromises the privacy of visits to v2 onion addresses.
What is the severity of CVE-2021-39246?
The severity of CVE-2021-39246 is medium with a CVSS score of 6.1.
How can CVE-2021-39246 be exploited?
CVE-2021-39246 can be exploited by an attacker comparing exact timestamps of locally logged onion-service visits to timestamp data collected by the destination.
Is Apple macOS or Linux Linux kernel affected by CVE-2021-39246?
No, Apple macOS and Linux Linux kernel are not affected by CVE-2021-39246.
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- collector/mitre-cve
- source/MITRE
- vendor/torproject
- canonical/torproject tor browser
- version/torproject tor browser/10.5.6
- version/torproject tor browser/11.0-alpha2
- version/torproject tor browser/11.0-alpha4
- vendor/apple
- canonical/apple macos
- vendor/linux
- canonical/linux linux kernel
- vendor/microsoft
- canonical/microsoft windows