CVE-2021-21281: Contiki-NG

Critical severity, CVSS 9.8. EPSS: 0.9% chance of exploitation in the next 30 days.

Contiki-NG is an open-source, cross-platform operating system for internet of things devices. A buffer overflow vulnerability exists in Contiki-NG versions prior to 4.6. After establishing a TCP socket using the tcp-socket library, it is possible for the remote end to send a packet with a data offset that is unvalidated. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.

Affected products

• Contiki-NG Contiki-NG: before 4.6 (fixed in 4.6)

Published 2021-06-18. Last modified 2026-06-17.