Is CVE-2021-21279 actively exploited?

No active exploitation of CVE-2021-21279 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21279 be exploited remotely?

Yes. CVE-2021-21279 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-21279?

CVE-2021-21279 has a CVSS score of 7.5 (HIGH).

HOME VULNERABILITIESCVE-2021-21279

HIGH

CVE-2021-21279

CWE-835Published: June 18, 2021· Updated: Jun 17, 2026

7.5

CVSS v3.1

Official Description

Contiki-NG is an open-source, cross-platform operating system for internet of things devices. In verions prior to 4.6, an attacker can perform a denial-of-service attack by triggering an infinite loop in the processing of IPv6 neighbor solicitation (NS) messages. This type of attack can effectively shut down the operation of the system because of the cooperative scheduling used for the main parts of Contiki-NG and its communication stack. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.

NVD Source

Technical Analysis

CVE-2021-21279 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.