{"id":"CVE-2023-49786","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-49786","generatedAt":"2026-10-28T02:17:15.135Z","title":"In Asterisk prior to versions 18.20.1, 20.5.1, and 21.0.1; as well as certified-asterisk prior to 18.9-cert6; Asterisk is susceptible to a DoS due to a race condition in the hello handshake phase of the DTLS protocol when handling DTLS-SRTP for media…","description":"Asterisk is an open source private branch exchange and telephony toolkit. In Asterisk prior to versions 18.20.1, 20.5.1, and 21.0.1; as well as certified-asterisk prior to 18.9-cert6; Asterisk is susceptible to a DoS due to a race condition in the hello handshake phase of the DTLS protocol when handling DTLS-SRTP for media setup. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable Asterisk servers for calls that rely on DTLS-SRTP. Commit d7d7764cb07c8a1872804321302ef93bf62cba05 contains a fix, which is part of versions 18.20.1, 20.5.1, 21.0.1, amd 18.9-cert6.","published":"2023-12-14T20:15:53.000Z","lastModified":"2026-06-17T06:36:28.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-703","CWE-362"],"affected":["digium/asterisk","sangoma/certified asterisk"],"epss":{"score":0.05295,"percentile":0.92524,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (5.29%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"security-advisories@github.com"},{"url":"http://seclists.org/fulldisclosure/2023/Dec/24","tags":["Exploit","Mailing List","Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"http://www.openwall.com/lists/oss-security/2023/12/15/7","tags":["Exploit","Mailing List"],"source":"security-advisories@github.com"},{"url":"https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race","tags":["Exploit"],"source":"security-advisories@github.com"},{"url":"https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html","source":"security-advisories@github.com"},{"url":"http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://seclists.org/fulldisclosure/2023/Dec/24","tags":["Exploit","Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/12/15/7","tags":["Exploit","Mailing List"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race","tags":["Exploit"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq","tags":["Exploit","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-49786","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}