Skip to content
Fencer Vulns
low 2.7

CVE-2021-20286 json

A flaw was found in libnbd 1.7.3.

published 2021-03-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7714

cvss
2.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

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.

Patch / fix

  • redhat libnbd 1.7.3
  • libnbd Debian 14, Debian 13, Debian 12 1.6.2-1

debian advisories DEBIAN-CVE-2021-20286

  • kubevirt SLE Module for Containers 15 SP3, SLE Module for Containers 15 SP2 0.40.0-5.11.2
  • containerized-data-importer SLE Module for Containers 15 SP2 1.30.0-5.3.2

suse advisories SUSE-SU-2021:2274-1

  • libnbd openSUSE Tumbleweed 1.9.3-1.2
  • kubevirt openSUSE Leap 15.3 0.40.0-5.11.2

opensuse advisories openSUSE-SU-2024:10961-1openSUSE-SU-2021:2274-1

  • libnbd Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 1.10.5-r0

alpine advisories ALPINE-CVE-2021-20286

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libnbd CBL-Mariner 2.0 1.12.1-1

azure linux advisories AZL-7265

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20286 updated cvss 2.7

libnbd: Assertion failure in nbd_unlocked_opt_go in lib/opt.c

  • Red Hat Enterprise Linux 8 Advanced Virtualization libnbd, nbdfuse, ocaml-libnbd, python3-libnbd, libnbd-bash-completion
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 8 libnbd, nbdfuse, ocaml-libnbd, python3-libnbd, libnbd-bash-completion Red Hat Enterprise Linux 8 Advanced Virtualization libnbd, nbdfuse, ocaml-libnbd, python3-libnbd, libnbd-bash-completion Red Hat Enterprise Linux 9 libnbd, nbdfuse, ocaml-libnbd, python3-libnbd, libnbd-bash-completion
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.14% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 2.7 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • n/a libnbd

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.