{"id":"CVE-2021-39246","details":"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).","modified":"2026-04-11T21:23:18.225502Z","published":"2021-09-24T19:15:07.147Z","references":[{"type":"ADVISORY","url":"https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/434"},{"type":"ADVISORY","url":"https://www.privacyaffairs.com/cve-2021-39246-tor-vulnerability"},{"type":"FIX","url":"https://gitlab.torproject.org/tpo/core/tor/-/commit/80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9"},{"type":"EVIDENCE","url":"https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-111.md"},{"type":"EVIDENCE","url":"https://sick.codes/sick-2021-111"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://gitlab.torproject.org/tpo/core/tor","events":[{"introduced":"0"},{"fixed":"80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9"}]},{"type":"GIT","repo":"https://gitlab.torproject.org/tpo/core/tor","events":[{"introduced":"0"},{"fixed":"80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9"}]}],"versions":["debian-version-0.0.1+0.0.2pre19-1","debian-version-0.0.1+0.0.2pre20-1","debian-version-0.0.1+0.0.2pre20-2","debian-version-0.0.1+0.0.2pre21-1","debian-version-0.0.1+0.0.2pre22-1","debian-version-0.0.1+0.0.2pre23-1","debian-version-0.0.1+0.0.2pre24-1","debian-version-0.0.1+0.0.2pre25-1","debian-version-0.0.1+0.0.2pre26-1","debian-version-0.0.1+0.0.2pre27-1","debian-version-0.0.2-1","debian-version-0.0.3-1","debian-version-0.0.4-1","debian-version-0.0.5+0.0.6rc2-1","debian-version-0.0.5+0.0.6rc3-1","debian-version-0.0.5+0.0.6rc4-1","debian-version-0.0.5-1","debian-version-0.0.6-1","debian-version-0.0.6.1-1","debian-version-0.0.6.2-1","debian-version-0.0.7+0.0.8rc1-1","debian-version-0.0.7-1","debian-version-0.0.7.1-1","debian-version-0.0.7.2+0.0.8pre2-1","debian-version-0.0.7.2+0.0.8pre3-1","debian-version-0.0.8+0.0.9pre1-1","debian-version-0.0.8+0.0.9pre2-1","debian-version-0.0.8+0.0.9pre3-1","debian-version-0.0.8+0.0.9pre4-1","debian-version-0.0.8+0.0.9pre5-1","debian-version-0.0.8+0.0.9pre5-2","debian-version-0.0.8+0.0.9pre6-1","debian-version-0.0.8+0.0.9rc1-1","debian-version-0.0.8+0.0.9rc2-1","debian-version-0.0.8+0.0.9rc3-1","debian-version-0.0.8+0.0.9rc5-1","debian-version-0.0.8+0.0.9rc6-1","debian-version-0.0.8+0.0.9rc7-1","debian-version-0.0.8-1","debian-version-0.0.9.1-1","debian-version-0.0.9.10-1","debian-version-0.0.9.2-1","debian-version-0.0.9.3-1","debian-version-0.0.9.4-1","debian-version-0.0.9.5-1","debian-version-0.0.9.6-1","debian-version-0.0.9.7-1","debian-version-0.0.9.8-1","debian-version-0.0.9.9-1","debian-version-0.1.0.1-rc-cvs-200503310807-1","debian-version-0.1.0.1-rc-cvs-200504010815-1","debian-version-0.1.0.10-0-pre.1","debian-version-0.1.0.11-0-pre.1","debian-version-0.1.0.11-1","debian-version-0.1.0.12-1","debian-version-0.1.0.13-1","debian-version-0.1.0.14-1","debian-version-0.1.0.14-2","debian-version-0.1.0.15-1","debian-version-0.1.0.16-1","debian-version-0.1.0.17-1","debian-version-0.1.0.2-rc-200504011500-1","debian-version-0.1.0.2-rc-200504011640-1","debian-version-0.1.0.2-rc-cvs-200504031300-1","debian-version-0.1.0.2-rc-cvs-200504061620-1","debian-version-0.1.0.2-rc-cvs-200504062112-1","debian-version-0.1.0.3-rc-200504080730-1","debian-version-0.1.0.3-rc-200504231430-1","debian-version-0.1.0.3-rc-cvs-200504231630-1","debian-version-0.1.0.4-rc-200504232130-1","debian-version-0.1.0.5-rc-200504272000-1","debian-version-0.1.0.7-rc-200505171420-1","debian-version-0.1.0.8-rc-1","debian-version-0.1.0.9-rc-1","debian-version-0.1.1.10-alpha-1","debian-version-0.1.1.11-alpha-1","debian-version-0.1.1.12-alpha-1","debian-version-0.1.1.13-alpha-1","debian-version-0.1.1.14-alpha-1","debian-version-0.1.1.15-rc-1","debian-version-0.1.1.16-rc-1","debian-version-0.1.1.17-rc-1","debian-version-0.1.1.18-rc-1","debian-version-0.1.1.19-rc-1","debian-version-0.1.1.20-1","debian-version-0.1.1.21-1","debian-version-0.1.1.22-1","debian-version-0.1.1.5-alpha-1","debian-version-0.1.1.6-alpha-1","debian-version-0.1.1.6-alpha-2","debian-version-0.1.1.7-alpha-1","debian-version-0.1.1.8-alpha-1","debian-version-0.1.1.9-alpha-1","tor-0.0.2","tor-0.0.2pre13","tor-0.0.2pre14","tor-0.0.2pre16","tor-0.0.2pre17","tor-0.0.2pre18","tor-0.0.2pre19","tor-0.0.2pre20","tor-0.0.2pre22","tor-0.0.2pre23","tor-0.0.2pre24","tor-0.0.2pre25","tor-0.0.2pre27","tor-0.0.2pre8","tor-0.0.3","tor-0.0.4","tor-0.0.5","tor-0.0.6","tor-0.0.6.1","tor-0.0.6.2","tor-0.0.6incompat-merged","tor-0.0.7","tor-0.0.7.1","tor-0.0.7.2","tor-0.0.7rc1","tor-0.0.8","tor-0.0.8.1","tor-0.0.8pre1","tor-0.0.8pre2","tor-0.0.8pre3","tor-0.0.8rc1","tor-0.0.8rc2","tor-0.0.9","tor-0.0.9.1","tor-0.0.9.10","tor-0.0.9.2","tor-0.0.9.3","tor-0.0.9.5","tor-0.0.9.6","tor-0.0.9.7","tor-0.0.9.9","tor-0.0.9pre1","tor-0.0.9pre2","tor-0.0.9pre3","tor-0.0.9pre4","tor-0.0.9pre5","tor-0.0.9pre6","tor-0.0.9rc1","tor-0.0.9rc2","tor-0.0.9rc3","tor-0.0.9rc4","tor-0.0.9rc5","tor-0.0.9rc6","tor-0.0.9rc7","tor-0.1.0.1-rc","tor-0.1.0.10","tor-0.1.0.11","tor-0.1.0.12","tor-0.1.0.13","tor-0.1.0.14","tor-0.1.0.15","tor-0.1.0.16","tor-0.1.0.17","tor-0.1.0.2-rc","tor-0.1.0.4-rc","tor-0.1.0.5-rc","tor-0.1.0.6-rc","tor-0.1.0.7-rc","tor-0.1.0.9-rc","tor-0.1.1.1-alpha","tor-0.1.1.10-alpha","tor-0.1.1.11-alpha","tor-0.1.1.12-alpha","tor-0.1.1.13-alpha","tor-0.1.1.14-alpha","tor-0.1.1.15-rc","tor-0.1.1.16-rc","tor-0.1.1.17-rc","tor-0.1.1.18-rc","tor-0.1.1.19-rc","tor-0.1.1.2-alpha","tor-0.1.1.20","tor-0.1.1.21","tor-0.1.1.22","tor-0.1.1.4-alpha","tor-0.1.1.5-alpha","tor-0.1.1.6-alpha","tor-0.1.1.7-alpha","tor-0.1.1.8-alpha","tor-0.1.1.9-alpha","tor-0.1.2.1-alpha","tor-0.1.2.2-alpha","tor-0.1.2.3-alpha","tor-0.1.2.4-alpha","tor-0.1.2.5-alpha","tor-0.1.2.6-alpha","tor-0.1.2.7-alpha","tor-0.1.2.8-beta","tor-0.1.2.9-rc","tor-0.2.0.1-alpha","tor-0.2.0.10-alpha","tor-0.2.0.11-alpha","tor-0.2.0.12-alpha","tor-0.2.0.13-alpha","tor-0.2.0.14-alpha","tor-0.2.0.15-alpha","tor-0.2.0.16-alpha","tor-0.2.0.17-alpha","tor-0.2.0.18-alpha","tor-0.2.0.19-alpha","tor-0.2.0.2-alpha","tor-0.2.0.20-rc","tor-0.2.0.3-alpha","tor-0.2.0.4-alpha@11197","tor-0.2.0.5-alpha","tor-0.2.0.6-alpha","tor-0.2.0.7-alpha","tor-0.2.0.8-alpha","tor-0.2.0.9-alpha","tor-0.2.1.1-alpha","tor-0.2.1.10-alpha","tor-0.2.1.11-alpha","tor-0.2.1.13-alpha","tor-0.2.1.14-rc","tor-0.2.1.2-alpha","tor-0.2.1.3-alpha","tor-0.2.1.4-alpha","tor-0.2.1.5-alpha","tor-0.2.1.6-alpha","tor-0.2.1.7-alpha","tor-0.2.1.8-alpha","tor-0.2.1.9-alpha","tor-0.2.2.1-alpha","tor-0.2.2.10-alpha","tor-0.2.2.11-alpha","tor-0.2.2.12-alpha","tor-0.2.2.13-alpha","tor-0.2.2.14-alpha","tor-0.2.2.15-alpha","tor-0.2.2.16-alpha","tor-0.2.2.2-alpha","tor-0.2.2.3-alpha","tor-0.2.2.4-alpha","tor-0.2.2.5-alpha","tor-0.2.2.6-alpha","tor-0.2.2.7-alpha","tor-0.2.2.8-alpha","tor-0.2.2.9-alpha","tor-0.2.3.1-alpha","tor-0.2.3.10-alpha","tor-0.2.3.11-alpha","tor-0.2.3.12-alpha","tor-0.2.3.13-alpha","tor-0.2.3.14-alpha","tor-0.2.3.15-alpha","tor-0.2.3.16-alpha","tor-0.2.3.17-beta","tor-0.2.3.2-alpha","tor-0.2.3.3-alpha","tor-0.2.3.4-alpha","tor-0.2.3.5-alpha","tor-0.2.3.6-alpha","tor-0.2.3.7-alpha","tor-0.2.3.8-alpha","tor-0.2.3.9-alpha","tor-0.2.4.1-alpha","tor-0.2.4.10-alpha","tor-0.2.4.2-alpha","tor-0.2.4.3-alpha","tor-0.2.4.4-alpha","tor-0.2.4.5-alpha","tor-0.2.4.6-alpha","tor-0.2.4.7-alpha","tor-0.2.4.8-alpha","tor-0.2.4.9-alpha","tor-0.2.5.1-alpha","tor-0.2.5.2-alpha","tor-0.2.5.3-alpha","tor-0.2.5.4-alpha","tor-0.2.5.5-alpha","tor-0.2.6.1-alpha","tor-0.2.6.2-alpha","tor-0.2.6.3-alpha","tor-0.2.7.0-root","tor-0.2.7.1-alpha","tor-0.2.7.2-alpha","tor-0.2.7.3-rc","tor-0.2.8.1-alpha","tor-0.2.8.2-alpha","tor-0.2.9.0-root","tor-0.2.9.1-alpha","tor-0.2.9.2-alpha","tor-0.2.9.3-alpha","tor-0.2.9.4-alpha","tor-0.3.0.1-alpha","tor-0.3.0.2-alpha","tor-0.3.0.3-alpha","tor-0.3.1.1-alpha","tor-0.3.1.2-alpha","tor-0.3.1.3-alpha","tor-0.3.2.1-alpha","tor-0.3.2.2-alpha","tor-0.3.3.0-alpha-dev","tor-0.3.3.1-alpha","tor-0.3.3.2-alpha","tor-0.3.4.0-alpha-dev","tor-0.3.4.1-alpha","tor-0.3.4.2-alpha","tor-0.3.5.0-alpha-dev","tor-0.3.5.1-alpha","tor-0.3.5.2-alpha","tor-0.3.5.3-alpha","tor-0.4.0.1-alpha","tor-0.4.1.0-alpha-dev","tor-0.4.1.1-alpha","tor-0.4.1.2-alpha","tor-0.4.2.1-alpha","tor-0.4.2.2-alpha","tor-0.4.3.0-alpha-dev","tor-0.4.3.1-alpha","tor-0.4.3.2-alpha","tor-0.4.4.0-alpha-dev","tor-0.4.5.0-alpha-dev","tor-0.4.5.1-alpha"],"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"10.5.6"}]},{"events":[{"introduced":"0"},{"last_affected":"11.0-alpha2"}]},{"events":[{"introduced":"0"},{"last_affected":"11.0-alpha4"}]},{"events":[{"introduced":"0"},{"last_affected":"10.5.6"}]},{"events":[{"introduced":"11.x"},{"last_affected":"11.0a4"}]}],"vanir_signatures_modified":"2026-04-11T21:23:18Z","vanir_signatures":[{"target":{"file":"src/core/or/connection_edge.c","function":"connection_ap_handshake_rewrite_and_attach"},"deprecated":false,"digest":{"function_hash":"270670856525417116219992913658386403585","length":8629},"id":"CVE-2021-39246-8a8397d2","signature_type":"Function","signature_version":"v1","source":"https://gitlab.torproject.org/tpo/core/tor@80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9"},{"signature_version":"v1","source":"https://gitlab.torproject.org/tpo/core/tor@80c404c4b79f3bcba3fc4585d4c62a62a04f3ed9","target":{"file":"src/core/or/connection_edge.c"},"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["208357041382853836769027119441242105408","140778957979783126231207539226265898353","321796730246266014274177898922617126753","320548936161662153568767541826974652117"]},"id":"CVE-2021-39246-f2d89d57","signature_type":"Line"}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-39246.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}