CVE-2020-28242

Name: CVE-2020-28242
Creator: NVD / NIST
Published: 2020-11-06T06:15:11.93+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.54%

Last modified Jun 17, 2026

CVE-2020-28242 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 1.54% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.54%

71.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-674

Affected Software

Vendor	Product	Versions
Asterisk	Certified Asterisk	<= 16.8.0
Sangoma	Asterisk	>= 13.0, < 13.37.1
Sangoma	Asterisk	>= 16.0, < 16.14.1
Sangoma	Asterisk	>= 17.0, < 17.8.1
Sangoma	Asterisk	>= 18.0, < 18.0.1
Fedoraproject	Fedora	33
Debian	Debian Linux	9.0

References

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/

Timeline

Published: Nov 6, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-28242?

How severe is CVE-2020-28242?

CVE-2020-28242 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.54% probability of exploitation in the next 30 days.

How do I fix CVE-2020-28242?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-28242?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST