CVE-2023-49786Asterisk susceptible to Denial of Service via DTLS Hello packets during call initiation
- 7.5HighCVSS base score
- 5.3%Exploitation in 30 daysEPSS · top 7.3% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By GitHub_M
- 14 days later
· 14 days later
Published
- 14 months later
· 14 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 5.3% · top 7.3% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
References
References7
- https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race (opens in a new tab)x_refsource_MISCx_transferred
- http://www.openwall.com/lists/oss-security/2023/12/15/7 (opens in a new tab)x_transferred
- http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html (opens in a new tab)x_transferred
- http://seclists.org/fulldisclosure/2023/Dec/24 (opens in a new tab)x_transferred
- https://lists.debian.org/debian-lts-announce/2023/12/msg00019.html (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-53705 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-49786)Record last updated .