Is CVE-2024-42491 in the CISA KEV catalog?

No. CVE-2024-42491 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2024-42491?

CVE-2024-42491 has a CVSS v3 base score of 5.7 (MEDIUM).

What is the EPSS score for CVE-2024-42491?

CVE-2024-42491 has an EPSS score of 0.55% (42th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2024-42491?

Upgrade asterisk on debian 11 to 1:16.28.0~dfsg-0+deb11u5 or later.

CVE & CISA-KEV Catalog

CVE-2024-42491

MEDIUM

5.7

CVSS v3

NVD

Description

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.

CWE-252 CWE-476NULL Pointer Dereference

How to fix

Remediation Available

asteriskDebian

Fixed in:1:16.28.0~dfsg-0+deb11u5CVE-2024-42491

Fixed in:1:20.9.3~dfsg+~cs6.14.60671435-1CVE-2024-42491

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.55%probability of exploitation in 30 days

42ndpercentile

Moderate risk: more likely to be exploited than 42% of all known CVEs.

References

Patch5

Vendor Advisory1

github.com

Other references1

lists.debian.org

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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.