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NVD / CVE Program· CNA GitHub_M

CVE-2024-42491: A malformed Contact or Record-Route URI in an incoming SIP request can cause Asterisk to crash when res_resolver_unbound is used

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.58% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: asterisk (Alpine:v3.17) 18.24.3-r0; asterisk (Alpine:v3.19) 20.9.3-r0; asterisk (Debian:11) 1:16.28.0~dfsg-0+deb11u5.

Low priority for now. Upgrade to asterisk (Alpine:v3.17) 18.24.3-r0; asterisk (Alpine:v3.19) 20.9.3-r0; asterisk (Debian:11) 1:16.28.0~dfsg-0+deb11u5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.7 · v3.1—No exploit Fix available
Published
Sep 5, 2024
Updated
Jun 17, 2026
EPSS
0.5% · 47th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.7
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
sangomaasterisk
sangomacertified asterisk

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • sangoma asteriskbefore 18.24.3
  • sangoma asterisk20.0.0 and later · before 20.9.3
  • sangoma asterisk21.0.0 and later · up to 21.4.3 inclusive
  • sangoma certified asteriskbefore 18.9
  • sangoma certified asterisk18.9
  • sangoma certified asterisk20.7

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • asterisk asterisk

    • < 18.24.3, >= 19.0.0, < 20.9.3, >= 21.0.0, < 21.4.3, < 18.9-cert12, >= 19.0, < 20.7-cert2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.17asteriskfrom 20.0.0 · before 18.24.3-r018.24.3-r0
Alpine:v3.19asteriskfrom 20.0.0 · before 20.9.3-r020.9.3-r0
Debian:11asteriskbefore 1:16.28.0~dfsg-0+deb11u51:16.28.0~dfsg-0+deb11u5
Debian:14asteriskbefore 1:20.9.3~dfsg+~cs6.14.60671435-11:20.9.3~dfsg+~cs6.14.60671435-1

Same product

sangoma: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-57520Insecure Permissions vulnerability in asterisk v22 allows a remote attacker to execute arbitrary code via the action_createconfig function.
    39Monitor
  • CVE-2026-23741ast_coredumper running as root sources ast_debug_tools.conf from /etc/asterisk; potentially leading to privilege escalation
    35Monitor
  • CVE-2025-57767Asterisk can crash from a specifically malformed Authorization header in an incoming SIP request
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2022-42706Dec 5, 2022 · An issue was discovered in Sangoma Asterisk through 16.28, 17 and 18 through 18.14, 19 through 19.6, and certified through 18.9-cert1.
    19Monitor
  • ← EarlierCVE-2024-35190May 17, 2024 · Asterisk' res_pjsip_endpoint_identifier_ip: wrongly matches ALL unauthorized SIP requests
    21Monitor
  • Later →CVE-2024-53566Dec 2, 2024 · An issue in the action_listcategories() function of Sangoma Asterisk v22/22.0.0/22.0.0-rc1/22.0.0-rc2/22.0.0-pre1 allows attackers to execut
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:asterisk18.24.3-r0 · Alpine:v3.17Package registry (OSV)
debian:asterisk1:20.9.3~dfsg+~cs6.14.60671435-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-252 · Unchecked Return Value

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records