{"id":"CVE-2019-8955","aliases":["ALPINE-CVE-2019-8955","DEBIAN-CVE-2019-8955","EUVD-2019-18342","GHSA-h3x5-p32h-w7q2","UBUNTU-CVE-2019-8955","USN-5036-1","openSUSE-SU-2019:1107-1","openSUSE-SU-2024:11469-1"],"status":"published","title":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2...","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","severity":{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.04572,"percentile":0.91683,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2019-02-21T23:00:00Z","modified":"2026-11-03T06:32:23Z","fixes":[{"ecosystem":"Alpine:v3.10","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.11","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.12","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.13","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.14","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.15","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.16","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.17","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.18","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"tor","fixed_in":["0.3.5.8-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.8","package":"tor","fixed_in":["0.3.3.12-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.9","package":"tor","fixed_in":["0.3.4.11-r0"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"tor","fixed_in":["0.3.5.8-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"tor","fixed_in":["0.3.5.8-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"tor","fixed_in":["0.3.5.8-1"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:18.04:LTS","package":"tor","fixed_in":["0.3.2.10-1ubuntu0.2~esm1"],"sources":["osv"]},{"ecosystem":"SUSE:Package 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Hub 12","package":"tor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.3.4.11-bp150.3.6.1"}]}]},{"source":"osv","ecosystem":"SUSE:Package Hub 15","package":"tor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.3.4.11-bp150.3.6.1"}]}]},{"source":"osv","ecosystem":"openSUSE:Leap 15.0","package":"tor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.3.4.11-bp150.3.6.1"}]}]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"tor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.6.7-2.2"}]}],"bundled":22}],"products":[{"vendor":"torproject","product":"tor"}],"references":[{"url":"http://www.securityfocus.com/bid/107136","tags":["vdb-entry","x_refsource_BID","x_transferred","Third Party Advisory","VDB Entry","advisory"]},{"url":"https://trac.torproject.org/projects/tor/ticket/29168","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","report"]},{"url":"https://blog.torproject.org/new-releases-tor-0402-alpha-0358-03411-and-03312","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","report"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00013.html","tags":["vendor-advisory","x_refsource_SUSE","x_transferred","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2019-8955"},{"url":"https://github.com/advisories/GHSA-h3x5-p32h-w7q2"},{"url":"https://security.alpinelinux.org/vuln/CVE-2019-8955","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2019-8955","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2019-8955","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-5036-1","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2019-8955","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-28089","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-28090","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-34548","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-34549","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-34550","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-38385","tags":["report"]},{"url":"https://lists.opensuse.org/archives/list/security-announce@lists.opensuse.org/thread/74WSDUB3VOMQJURXHX3XYEUPWWZJQQ2L/#74WSDUB3VOMQJURXHX3XYEUPWWZJQQ2L","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1126340","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2019-8955","tags":["web"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2016-1254","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-0375","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-0376","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-0377","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-0380","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-8819","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-8820","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-8821","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-8822","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-8823","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-0490","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-0491","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-10592","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-10593","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-15572","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-28089","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-28090","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-34548","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-34549","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-34550","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-38385","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:00:00Z","modified":"2024-08-04T21:31:37.55Z","updated_at":"2026-11-02T14:20:21.703364Z"}],"euvd":[{"id":"EUVD-2019-18342","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:00:00Z","modified":"2024-08-04T21:31:37Z","updated_at":"2026-11-03T03:06:40.408517Z"}],"ghsa":[{"id":"GHSA-h3x5-p32h-w7q2","title":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2...","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2022-05-13T01:22:57Z","modified":"2023-02-01T05:07:03Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:50:28.399252Z"}],"nvd":[{"id":"CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:29:00.267Z","modified":"2026-06-17T02:42:50.857Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:05:04.689371Z"}],"osv":[{"id":"ALPINE-CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:29:00.267Z","modified":"2026-11-03T06:32:23.001002023Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T07:17:57.723967Z"},{"id":"CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:29:00.267Z","modified":"2026-10-24T10:30:23.182013047Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:12.974481Z"},{"id":"DEBIAN-CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:29:00.267Z","modified":"2026-09-21T07:03:15.599323717Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:32.57265Z"},{"id":"UBUNTU-CVE-2019-8955","description":"In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.","status":"published","published":"2019-02-21T23:29:00Z","modified":"2026-02-04T02:39:03.213096Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:54:22.212782Z"},{"id":"openSUSE-SU-2019:1107-1","title":"Security update for tor","description":"This update for tor to version 0.3.4.11 fixes the following issues:\n\nSecurity issue fixed:\n\n- CVE-2019-8955: Fixed a vulnerability in the KIST cell scheduler which could lead\n  to memory exhaustion and finally Denial-of-Service (bsc#1126340). \n","status":"published","published":"2019-04-02T11:00:27Z","modified":"2026-02-04T02:50:22.017886Z","updated_at":"2026-11-02T16:58:30.784344Z"},{"id":"openSUSE-SU-2024:11469-1","title":"tor-0.4.6.7-2.2 on GA media","description":"These are all security issues fixed in the tor-0.4.6.7-2.2 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:58:38.644616Z","updated_at":"2026-11-02T16:58:35.195147Z"},{"id":"USN-5036-1","title":"tor vulnerabilities","description":"It was discovered that Tor incorrectly handled certain memory operations. A\nremote attacker could use this issue to cause a denial of service. This issue\nonly affected Ubuntu 18.04 ESM. (CVE-2019-8955)\n\nIt was discovered that Tor did not properly handle the input length to\ndump_desc() function. A remote attacker could use this issue to cause a denial\nof service. This issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and\nUbuntu 20.04 ESM. (CVE-2021-28089)\n\nIt was discovered that Tor did not properly sanitize the relay nickname in\ndirvote_add_signatures_to_pending_consensus() function. An attacker could\npossibly use this issue to cause an assertion failure and then cause a denial\nof service. (CVE-2021-28090)\n\nIt was discovered that Tor did not properly validate the layer hint on\nhalf-open streams. A remote attacker could possibly use this issue to bypass\nthe access control, leading to remote code execution. This issue only affected\nUbuntu 20.04 ESM. (CVE-2021-34548)\n\nIt was discovered that Tor was using an insecure hash function. A remote\nattacker could use this issue to cause a denial of service. This issue only\naffected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and Ubuntu 20.04 ESM.\n(CVE-2021-34549)\n\nIt was discovered that Tor did not properly manage memory under certain\ncircumstances. If a user were tricked into opening a specially crafted request,\na remote attacker could possibly use this issue to cause a crash, resulting in\na denial of service, or possibly reading sensitive data. This issue only\naffected Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-34550)\n\nIt was discovered that Tor mishandles the relationship between batch-signature\nverification and single-signature verification. An attacker could possibly use\nthis issue to cause an assertion failure and then cause a denial of service.\nThis issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and Ubuntu 20.04\nESM. (CVE-2021-38385)\n","status":"published","published":"2022-10-04T11:04:57Z","modified":"2026-06-29T13:49:26.448825711Z","updated_at":"2026-11-02T16:58:15.683829Z"}]}}