HOME VULNERABILITIESCVE-2020-28242

MEDIUM

CVE-2020-28242

CWE-674Published: November 6, 2020· Updated: Jun 17, 2026

6.5

CVSS v3.1

Official Description

An issue was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1 and Certified Asterisk before 16.8-cert5. If Asterisk is challenged on an outbound INVITE and the nonce is changed in each response, Asterisk will continually send INVITEs in a loop. This causes Asterisk to consume more and more memory since the transaction will never terminate (even if the call is hung up), ultimately leading to a restart or shutdown of Asterisk. Outbound authentication must be configured on the endpoint for this to occur.

Technical Analysis

CVE-2020-28242 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.Low

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Affected Vendors & Products

asterisk1 product(s)

certified asterisk

Debian1 product(s)

debian linux

Fedora1 product(s)

fedora

sangoma1 product(s)

asterisk

Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://downloads.asterisk.org/pub/security/AST-2020-002.html

ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/04/msg00001.html

ADVISORYhttp://downloads.asterisk.org/pub/security/AST-2020-002.html

ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/04/msg00001.html

All References (6)

→

http://downloads.asterisk.org/pub/security/AST-2020-002.htmlVendor Advisory

→

https://lists.debian.org/debian-lts-announce/2022/04/msg00001.htmlMailing List · Third Party Advisory

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QUS54QTQCYKR36EIULYD544GXDA644HB/

→

http://downloads.asterisk.org/pub/security/AST-2020-002.htmlVendor Advisory

→

https://lists.debian.org/debian-lts-announce/2022/04/msg00001.htmlMailing List · Third Party Advisory

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QUS54QTQCYKR36EIULYD544GXDA644HB/

Quick Facts

CVE IDCVE-2020-28242

CVSS Score6.5 / 10

SeverityMEDIUM

WeaknessCWE-674

CISA KEVNo

Affected4 vendor(s)

PublishedNov 6, 2020

Related CVEs (CWE-674)

CVE-2018-1000618

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2020-28242 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.

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