What is CVE-2021-38387?

CVE-2021-38387 is a high-severity vulnerability in Contiki-Os Contiki, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-08-10.

How severe is CVE-2021-38387?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Contiki-Os Contiki

CVE-2021-38387

In Contiki 3.0, a Telnet server that silently quits (before disconnection with clients) leads to connected clients entering an infinite loop and waiting forever, which may cause excessive CPU consumption.

Published 2021-08-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (61.5th percentile), scored 2026-10-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.5% 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-Os Contiki — versions 3.0

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

github.com/contiki-os/contiki/issues/2688 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-38387?: CVE-2021-38387 is a high-severity vulnerability in Contiki-Os Contiki, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-08-10.
How severe is CVE-2021-38387?: High severity. CVSS v3 base score is 7.5 out of 10.