What is CVE-2021-20286?

CVE-2021-20286 is a low-severity vulnerability in Red Hat Enterprise Linux, classified under Reachable Assertion. CVSS score: 2.7/10. Published 2021-03-15.

How severe is CVE-2021-20286?

Low severity. CVSS v3 base score is 2.7 out of 10.

Vulnerability in Red Hat Enterprise Linux

CVE-2021-20286

A flaw was found in libnbd 1.7.3. An assertion failure in nbd_unlocked_opt_go in ilb/opt.c may lead to denial of service.

Published 2021-03-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.011 (66.0th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Red Hat Enterprise Linux — versions 8.3.0
Red Hat Libnbd
Libnbd — versions libnbd 1.7.3

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
gitlab.com/nbdkit/libnbd/-/commit/fb4440de9cc76e9c14bd3ddf3333e78621f40ad0 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-20286?: CVE-2021-20286 is a low-severity vulnerability in Red Hat Enterprise Linux, classified under Reachable Assertion. CVSS score: 2.7/10. Published 2021-03-15.
How severe is CVE-2021-20286?: Low severity. CVSS v3 base score is 2.7 out of 10.