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CVE-2021-39246

6.1 · MEDIUM

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.

Published Sep 24, 2021CWE-532EPSS 0.47%

Overview

CVE-2021-39246 is a medium-severity vulnerability. It was published on September 24, 2021 and has a CVSS 3.1 base score of 6.1 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.1, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical description

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).

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/sickcodes/security/blob/master/advisories/SICK-2021-111.mdRefgitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9Refgitlab.torproject.org/tpo/core/tor/-/merge_requests/434Refsick.codes/sick-2021-111Refwww.privacyaffairs.com/cve-2021-39246-tor-vulnerabilityGitHubgithub.com/sickcodes/security/blob/master/advisories/SICK-2021-111.mdRefgitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9Refgitlab.torproject.org/tpo/core/tor/-/merge_requests/434Refsick.codes/sick-2021-111Refwww.privacyaffairs.com/cve-2021-39246-tor-vulnerability

How CyberStrike helps

Frequently asked questions

What is CVE-2021-39246?

CVE-2021-39246 is a medium-severity vulnerability. It was published on September 24, 2021 and has a CVSS 3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2021-39246?

This vulnerability has a CVSS 3.1 base score of 6.1, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-39246?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-39246?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-39246 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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