CVE-2021-42143

Name: CVE-2021-42143
Creator: NVD / NIST
Published: 2024-01-24T18:15:08.08+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.81%

Last modified Jun 17, 2026

CVE-2021-42143 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. An infinite loop bug exists during the handling of a ClientHello handshake message. EPSS estimates a 0.81% chance of exploitation in the next 30 days.

Description

An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. An infinite loop bug exists during the handling of a ClientHello handshake message. This bug allows remote attackers to cause a denial of service by sending a malformed ClientHello handshake message with an odd length of cipher suites, which triggers an infinite loop (consuming all resources) and a buffer over-read that can disclose sensitive information.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

0.81%

52.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Contiki-Ng	Tinydtls	<= 2018-08-30

References

https://seclists.org/fulldisclosure/2024/Jan/16Mailing List, Third Party Advisory
http://seclists.org/fulldisclosure/2024/Jan/16
https://seclists.org/fulldisclosure/2024/Jan/16Mailing List, Third Party Advisory

Timeline

Published: Jan 24, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42143?

How severe is CVE-2021-42143?

CVE-2021-42143 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42143?

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-2021-42143?

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

Scan your code now

Source: NVD / NIST