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Vulnerability record · CVE-2023-49786 · published 14 December 2023

CVE-2023-49786: Digium asterisk race condition vulnerability

Digium · Asterisk

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.

5.9 CVSS 3.1 Medium EPSS 5.3% · top 7.7% CWE-703 · CWE-703CWE-362 · Race condition
5.9CVSS 3.1 base score
5.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
14References, 10 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html ExploitThird Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2023/Dec/24 ExploitMailing ListThird Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/15/7 ExploitMailing List
https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race Exploit
https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05 Patch
https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq ExploitVendor Advisory
https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html
http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html ExploitThird Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2023/Dec/24 ExploitMailing ListThird Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/15/7 ExploitMailing List
https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race Exploit
https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05 Patch
https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq ExploitVendor Advisory
https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-26651Digium asterisk sql injection vulnerabilityAn issue was discovered in Asterisk through 19.x and Certified Asterisk through 16.8-cert13. The func_odbc module provides possibly inadequate escapi…EPSS 7.0%9.8CVE-2017-14100Digium asterisk os command injection vulnerabilityIn Asterisk 11.x before 11.25.2, 13.x before 13.17.1, and 14.x before 14.6.1 and Certified Asterisk 11.x before 11.6-cert17 and 13.x before 13.13-cer…EPSS 15%9.1CVE-2022-26499Digium asterisk server-side request forgery (ssrf) vulnerabilityAn SSRF issue was discovered in Asterisk through 19.x. When using STIR/SHAKEN, it's possible to send arbitrary requests (such as GET) to interfaces s…EPSS 7.8%9.0CVE-2014-8418Digium certified asterisk permissions and access controls vulnerabilityThe DB dialplan function in Asterisk Open Source 1.8.x before 1.8.32, 11.x before 11.1.4.1, 12.x before 12.7.1, and 13.x before 13.0.1 and Certified …EPSS 3.6%9.0CVE-2011-1599Digium asterisk improper input validation vulnerabilitymanager.c in the Manager Interface in Asterisk Open Source 1.4.x before 1.4.40.1, 1.6.1.x before 1.6.1.25, 1.6.2.x before 1.6.2.17.3, and 1.8.x befor…EPSS 3.1%8.8CVE-2026-23741Sangoma asterisk uncontrolled search path element vulnerabilityAsterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2, the ast…EPSS 0.18%8.8CVE-2019-18610Digium asterisk missing authorization vulnerabilityAn issue was discovered in manager.c in Sangoma Asterisk through 13.x, 16.x, 17.x and Certified Asterisk 13.21 through 13.21-cert4. A remote authenti…EPSS 30%8.8CVE-2017-16671Digium asterisk memory buffer overflow vulnerabilityA Buffer Overflow issue was discovered in Asterisk Open Source 13 before 13.18.1, 14 before 14.7.1, and 15 before 15.1.1 and Certified Asterisk 13.13…EPSS 3.3%

Source: NIST National Vulnerability Database (record CVE-2023-49786), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.