CVE-2024-42491
MEDIUMDescription
Asterisk is an open-source private branch exchange (PBX). Prior to versions 18.24.3, 20.9.3, and 21.4.3 of Asterisk and versions 18.9-cert12 and 20.7-cert2 of certified-asterisk, if Asterisk attempts to send a SIP request to a URI whose host portion starts with `.1` or `[.1]`, and res_resolver_unbound is loaded, Asterisk will crash with a SEGV. To receive a patch, users should upgrade to one of the following versions: 18.24.3, 20.9.3, 21.4.3, certified-18.9-cert12, certified-20.7-cert2. Two workarounds are available. Disable res_resolver_unbound by setting `noload = res_resolver_unbound.so` in modules.conf, or set `rewrite_contact = yes` on all PJSIP endpoints. NOTE: This may not be appropriate for all Asterisk configurations.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 43% of all known CVEs.
References
Related Vulnerabilities
Other CWE-252 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2005-4360 | High | 7.8 | 87% | - | - |
| CVE-2007-3798 | Critical | 9.8 | 70% | - | Fix |
| CVE-2010-0211 | Critical | 9.8 | 28% | - | Fix |
| CVE-2022-23626 | High | 8.5 | 9.9% | - | Fix |
| CVE-2019-10902 | High | 7.5 | 4.7% | - | - |
| CVE-2018-20216 | High | 7.5 | 3.9% | - | Fix |
Common questions
How do I fix CVE-2024-42491?
Upgrade asterisk on debian 11 to 1:16.28.0~dfsg-0+deb11u5 or later.
Is CVE-2024-42491 being actively exploited?
Not that we know of. CVE-2024-42491 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.55% is the estimated probability that it will be exploited in the next 30 days. That is higher than 43% of all scored CVEs.
How severe is CVE-2024-42491?
CVE-2024-42491 has a CVSS v3 base score of 5.7, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2024-42491 affect?
Published advisories record a fix for asterisk (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.