How severe is CVE-2024-42491?

CVE-2024-42491 has a CVSS 3.x base score of 5.7, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2024-42491 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-42491?

CVE-2024-42491 primarily affects Sangoma Asterisk. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-42491?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2024-42491 have an EU (EUVD) identifier?

Yes. CVE-2024-42491 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-39644.

When was CVE-2024-42491 published?

CVE-2024-42491 was published on 2024-09-05 and last updated on 2026-06-17.

CVE-2024-42491

CVE-2024-42491 is a medium-severity vulnerability in Sangoma Asterisk with a CVSS 3.x base score of 5.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-252.

Key facts

Severity: Medium (CVSS 3.x base score 5.7)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-39644
Weakness: CWE-252
Affected product: Sangoma Asterisk
Published: 2024-09-05
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2024-42491?: 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 severe is CVE-2024-42491?: CVE-2024-42491 has a CVSS 3.x base score of 5.7, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-42491 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-42491?: CVE-2024-42491 primarily affects Sangoma Asterisk. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-42491?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-42491 have an EU (EUVD) identifier?: Yes. CVE-2024-42491 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-39644.
When was CVE-2024-42491 published?: CVE-2024-42491 was published on 2024-09-05 and last updated on 2026-06-17.

References

Affected products (21)

cpe:2.3:a:sangoma:asterisk:*:*:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:*:*:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:-:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert1:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert1-rc1:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert10:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert11:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert2:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert3:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert4:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert5:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert6:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert7:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert8:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert8-rc1:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert8-rc2:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:18.9:cert9:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1-rc1:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1-rc2:*:*:*:*:*:*
cpe:2.3:a:sangoma:certified_asterisk:20.7:cert2:*:*:*:*:*:*

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