CVE-2021-32771

Name: CVE-2021-32771
Creator: NVD / NIST
Published: 2022-08-04T21:15:07.907+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 1.03%

Last modified Jun 17, 2026

CVE-2021-32771 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. Contiki-NG is an open-source, cross-platform operating system for IoT devices. In affected versions it is possible to cause a buffer overflow when copying an IPv6 address prefix in the RPL-Classic implementation in Contiki-NG. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

Description

Contiki-NG is an open-source, cross-platform operating system for IoT devices. In affected versions it is possible to cause a buffer overflow when copying an IPv6 address prefix in the RPL-Classic implementation in Contiki-NG. In order to trigger the vulnerability, the Contiki-NG system must have joined an RPL DODAG. After that, an attacker can send a DAO packet with a Target option that contains a prefix length larger than 128 bits. The problem was fixed after the release of Contiki-NG 4.7. Users unable to upgrade may apply the patch in Contiki-NG PR #1615.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

1.03%

59.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-120

Affected Software

Vendor	Product	Versions
Contiki-Ng	Contiki-Ng	< 4.8

References

https://github.com/contiki-ng/contiki-ng/pull/1615Patch, Third Party Advisory
https://github.com/contiki-ng/contiki-ng/pull/1615/commits/587ae59956e00316fd44fd7072ac3a6a07b4b20fPatch, Third Party Advisory
https://github.com/contiki-ng/contiki-ng/releases/tag/release%2Fv4.8Third Party Advisory
https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-jqjf-v7v9-xp6wThird Party Advisory
https://github.com/contiki-ng/contiki-ng/pull/1615Patch, Third Party Advisory
https://github.com/contiki-ng/contiki-ng/pull/1615/commits/587ae59956e00316fd44fd7072ac3a6a07b4b20fPatch, Third Party Advisory
https://github.com/contiki-ng/contiki-ng/releases/tag/release%2Fv4.8Third Party Advisory
https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-jqjf-v7v9-xp6wThird Party Advisory

Timeline

Published: Aug 4, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-32771?

How severe is CVE-2021-32771?

CVE-2021-32771 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2021-32771?

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-2021-32771?

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

Scan your code now

Source: NVD / NIST