What is CVE-2021-21282?

CVE-2021-21282 is a high-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.6/10. Published 2021-06-18.

How severe is CVE-2021-21282?

High severity. CVSS v3 base score is 8.6 out of 10.

Buffer overflow in Contiki-Ng

CVE-2021-21282

Contiki-NG is an open-source, cross-platform operating system for internet of things devices. In versions prior to 4.5, buffer overflow can be triggered by an input packet when using either of Contiki-NG's two RPL implementations in source-routing mode. The problem has been patched in Contiki-NG 4.5. Users can apply the patch for this vulnerability out-of-band as a workaround.

Vulnerability class: Buffer Overflow

Published 2021-06-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.010 (61.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Contiki-Ng — versions < 4.5

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

github.com/contiki-ng/contiki-ng/security/advisories/GHSA-6xf2-77gf-fgjx (Patch, Third Party Advisory)
github.com/contiki-ng/contiki-ng/pull/1183 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21282?: CVE-2021-21282 is a high-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.6/10. Published 2021-06-18.
How severe is CVE-2021-21282?: High severity. CVSS v3 base score is 8.6 out of 10.