Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-49786 is a high-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Sangoma Certified Asterisk. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 8% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-53705
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Implements explicit check and handling for the exceptional condition of audit logging process failure.
Accurate timestamps from internal clocks enable detection of race conditions by providing reliable event ordering in audit logs.
Establishing and monitoring system metrics with correlation and response actions helps identify and address improper handling of exceptional conditions.
Provides a defined response to detected conditions by restricting operation, ensuring exceptional conditions are handled rather than ignored or mishandled.
Contingency training equips users with defined procedures to check and respond to exceptional conditions during disruptions, reducing exploitation of mishandled errors.
Testing verifies the system's ability to detect, handle, and recover from exceptional conditions as part of the plan, reducing exploitability of improper exception handling.
Regular updates keep contingency procedures aligned with system changes, providing structured handling for exceptional conditions that would otherwise allow unmitigated exploitation.
Policy defines checks and handling for exceptional conditions arising from security incidents.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.8.25 mandates secure SDLC practices (secure coding guidelines, security requirements, checkpoints, testing including code scans/penetration tests, developer training) that reach race conditions in concurrent code, but only as one slice of a broad requirement whose implementation scope and rigour are left to the organisation.
A.8.26 only requires that security requirements (including resilience against attacks like SQL injection) be identified and specified during development or acquisition; it does not itself remove, fix, or eliminate any exceptional-condition handling defects already present in code.
Secure architecture principles require proper synchronization and resource isolation, addressing the root cause of CWE-362.
A.8.28 mandates secure coding practices, principles, defect removal during coding/review, and prohibiting insecure techniques that directly produce improper exception handling; this removes most instances of the first-party code defect, with a bounded remainder in incomplete adoption or edge-case defects not captured by the baseline.
Security testing can detect race conditions, but does not prevent them at design or coding time.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-703, a pillar-level weakness, and none of its children carries one either.
- No fine-grained STIG row for CWE-362, a class-level weakness, and none of its children carries one either.