Asterisk susceptible to Denial of Service via DTLS Hello packets during call initiation
Priority HIGH 72CWE-703Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.05295 92nd percentileScored 2026-11-07
Public exploit Yes 5 exploit referencesTagged by NVD
Fix Fixed asterisk (asterisk): 18.20.1, 20.5.1, 18.9-cert6
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| asterisk | asterisk | before 18.20.1; 19.0.0 to before 20.5.1; = 21.0.0; before 18.9-cert6 | 18.20.1, 20.5.1, 18.9-cert6 | Patch available | CNA |
- asterisk Vendorasterisk Affected before 18.20.1; 19.0.0 to before 20.5.1; = 21.0.0; before 18.9-cert6 Fixed in 18.20.1, 20.5.1, 18.9-cert6 Patch available CNA
CPE configurations NVD · 30
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:* | before 18.20.1; 19.0.0 to before 20.5.1 | Vulnerable | Digium |
| cpe:2.3:a:digium:asterisk:21.0.0:*:*:*:*:*:*:* | 21.0.0 | Vulnerable | Digium |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:*:*:*:*:*:*:* | 13.13.0 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1:*:*:*:*:*:* | 13.13.0 cert1 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc1:*:*:*:*:*:* | 13.13.0 cert1-rc1 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc2:*:*:*:*:*:* | 13.13.0 cert1-rc2 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc3:*:*:*:*:*:* | 13.13.0 cert1-rc3 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc4:*:*:*:*:*:* | 13.13.0 cert1-rc4 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert2:*:*:*:*:*:* | 13.13.0 cert2 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert3:*:*:*:*:*:* | 13.13.0 cert3 | Vulnerable | Sangoma |
- cpe:2.3:a:digium:asterisk:*:*:*:*:*:*:*:* Versions before 18.20.1; 19.0.0 to before 20.5.1 Vulnerable ·Digium
- cpe:2.3:a:digium:asterisk:21.0.0:*:*:*:*:*:*:* Versions 21.0.0 Vulnerable ·Digium
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:*:*:*:*:*:*:* Versions 13.13.0 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1:*:*:*:*:*:* Versions 13.13.0 cert1 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc1:*:*:*:*:*:* Versions 13.13.0 cert1-rc1 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc2:*:*:*:*:*:* Versions 13.13.0 cert1-rc2 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc3:*:*:*:*:*:* Versions 13.13.0 cert1-rc3 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert1-rc4:*:*:*:*:*:* Versions 13.13.0 cert1-rc4 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert2:*:*:*:*:*:* Versions 13.13.0 cert2 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:cert3:*:*:*:*:*:* Versions 13.13.0 cert3 Vulnerable ·Sangoma
Show 20 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:rc1:*:*:*:*:*:* | 13.13.0 rc1 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:13.13.0:rc2:*:*:*:*:*:* | 13.13.0 rc2 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:-:*:*:*:*:*:* | 16.8.0 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert1:*:*:*:*:*:* | 16.8.0 cert1 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert10:*:*:*:*:*:* | 16.8.0 cert10 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert11:*:*:*:*:*:* | 16.8.0 cert11 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert12:*:*:*:*:*:* | 16.8.0 cert12 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert2:*:*:*:*:*:* | 16.8.0 cert2 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert3:*:*:*:*:*:* | 16.8.0 cert3 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert4:*:*:*:*:*:* | 16.8.0 cert4 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert5:*:*:*:*:*:* | 16.8.0 cert5 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert6:*:*:*:*:*:* | 16.8.0 cert6 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert7:*:*:*:*:*:* | 16.8.0 cert7 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert8:*:*:*:*:*:* | 16.8.0 cert8 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert9:*:*:*:*:*:* | 16.8.0 cert9 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:18.9:cert1:*:*:*:*:*:* | 18.9 cert1 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:18.9:cert2:*:*:*:*:*:* | 18.9 cert2 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:18.9:cert3:*:*:*:*:*:* | 18.9 cert3 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:18.9:cert4:*:*:*:*:*:* | 18.9 cert4 | Vulnerable | Sangoma |
| cpe:2.3:a:sangoma:certified_asterisk:18.9:cert5:*:*:*:*:*:* | 18.9 cert5 | Vulnerable | Sangoma |
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:rc1:*:*:*:*:*:* Versions 13.13.0 rc1 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:13.13.0:rc2:*:*:*:*:*:* Versions 13.13.0 rc2 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:-:*:*:*:*:*:* Versions 16.8.0 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert1:*:*:*:*:*:* Versions 16.8.0 cert1 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert10:*:*:*:*:*:* Versions 16.8.0 cert10 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert11:*:*:*:*:*:* Versions 16.8.0 cert11 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert12:*:*:*:*:*:* Versions 16.8.0 cert12 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert2:*:*:*:*:*:* Versions 16.8.0 cert2 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert3:*:*:*:*:*:* Versions 16.8.0 cert3 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert4:*:*:*:*:*:* Versions 16.8.0 cert4 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert5:*:*:*:*:*:* Versions 16.8.0 cert5 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert6:*:*:*:*:*:* Versions 16.8.0 cert6 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert7:*:*:*:*:*:* Versions 16.8.0 cert7 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert8:*:*:*:*:*:* Versions 16.8.0 cert8 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:16.8.0:cert9:*:*:*:*:*:* Versions 16.8.0 cert9 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:18.9:cert1:*:*:*:*:*:* Versions 18.9 cert1 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:18.9:cert2:*:*:*:*:*:* Versions 18.9 cert2 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:18.9:cert3:*:*:*:*:*:* Versions 18.9 cert3 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:18.9:cert4:*:*:*:*:*:* Versions 18.9 cert4 Vulnerable ·Sangoma
- cpe:2.3:a:sangoma:certified_asterisk:18.9:cert5:*:*:*:*:*:* Versions 18.9 cert5 Vulnerable ·Sangoma
Remediation
- Fix · CNA asterisk (asterisk) Fixed in 18.20.1, 20.5.1, 18.9-cert6
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2023-49786
References
Exploit 5
- https://github.com/asterisk/asterisk/security/advisories/GHSA-hxj9-xwr8-w8pq
- https://github.com/EnableSecurity/advisories/tree/master/ES2023-01-asterisk-dtls-hello-race
- http://www.openwall.com/lists/oss-security/2023/12/15/7
- http://packetstormsecurity.com/files/176251/Asterisk-20.1.0-Denial-Of-Service.html
- http://seclists.org/fulldisclosure/2023/Dec/24
More asterisk vulnerabilities
- TI-2025-30244 Using malformed From header can forge identity with ";" or NULL in name portion CVSS 3.1HIGH 7.7
- TI-2024-28351 Asterisk allows `Write=originate` as sufficient permissions for code execution / `System()` dialplan CVSS 3.1HIGH 8.8
- TI-2025-00959 Asterisk Unsafe Shell Sourcing in safe_asterisk Leads to Local Privilege Escalation CVSS 4.0HIGH 7.0
- TI-2025-34699 Asterisk remotely exploitable leak of RTP UDP ports and internal resources CVSS 3.1MEDIUM 6.5
- TI-2025-31747 Asterisk is Vulnerable to Remote DoS and possible RCE Attacks During Memory Allocation CVSS 3.1MEDIUM 6.5
- TI-2023-26930 Asterisk Path Traversal vulnerability CVSS 3.1HIGH 7.5
Sources
- CVE-2023-49786 · CVE Program
- CVE-2023-49786 · NVD
- FIRST EPSS
- CVE-2023-49786 · Red Hat security data · CC BY 4.0
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