What is CVE-2020-24336?

CVE-2020-24336 is a critical-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-12-11.

How severe is CVE-2020-24336?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Contiki-Ng

CVE-2020-24336

An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. The code for parsing Type A domain name answers in ip64-dns64.c doesn't verify whether the address in the answer's length is sane. Therefore, when copying an address of an arbitrary length, a buffer overflow can occur. This bug can be exploited whenever NAT64 is enabled.

Vulnerability class: Buffer Overflow

Published 2020-12-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.591 (99.1th percentile), scored 2026-10-29.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.591 · newest: 0.591 · change: 0.000

Affected products

Weakness classification (CWE)

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

References

www.kb.cert.org/vuls/id/815128 (US Government Resource, Third Party Advisory)
us-cert.cisa.gov/ics/advisories/icsa-20-343-01 (US Government Resource, Third Party Advisory)

Frequently asked questions

What is CVE-2020-24336?: CVE-2020-24336 is a critical-severity vulnerability in Contiki-Ng, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-12-11.
How severe is CVE-2020-24336?: Critical severity. CVSS v3 base score is 9.8 out of 10.