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Fencer Vulns
high 7.5

CVE-2020-12662 json

Unbound before 1.10.1 has Insufficient Control of Network Message Volume, aka an "NXNSAttack" issue.

published 2020-05-19 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4961

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

Unbound before 1.10.1 has Insufficient Control of Network Message Volume, aka an "NXNSAttack" issue. This is triggered by random subdomains in the NSDNAME in NS records.

Patch / fix

  • nlnetlabs unbound 1.10.1
  • unbound Debian 14, Debian 13, Debian 12 1.10.1-1

debian advisories DEBIAN-CVE-2020-12662

  • unbound Ubuntu 18.04 LTS 1.6.7-1ubuntu2.3
  • unbound Ubuntu 20.04 LTS 1.9.4-2ubuntu1.1

ubuntu advisories UBUNTU-CVE-2020-12662

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • unbound RHEL 6 1.4.20-29.el6_10.1
  • unbound-libs RHEL 6 1.4.20-29.el6_10.1
  • unbound-python RHEL 6 1.4.20-29.el6_10.1
  • unbound RHEL 7 1.6.6-4.el7_8
  • unbound-libs RHEL 7 1.6.6-4.el7_8
  • unbound-python RHEL 7 1.6.6-4.el7_8
  • unbound RHEL 8 1.7.3-11.el8_2
  • unbound-libs RHEL 8 1.7.3-11.el8_2

red hat advisories RHSA-2020:4181RHSA-2020:2640RHSA-2020:2414RHSA-2020:2418RHSA-2020:2419RHSA-2020:2416

  • unbound SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 1.6.8-3.6.1
  • unbound SLE Module for Basesystem 15 SP2, SLE Module for Basesystem 15 SP1 1.6.8-10.3.1

suse advisories SUSE-SU-2020:1819-1SUSE-SU-2020:1772-1

  • unbound openSUSE Tumbleweed 1.13.2-1.2
  • unbound openSUSE Leap 15.2 1.6.8-lp152.9.3.1
  • libunbound-devel-mini openSUSE Leap 15.2 1.6.8-lp152.9.3.1
  • unbound openSUSE Leap 15.1 1.6.8-lp151.8.3.1
  • libunbound-devel-mini openSUSE Leap 15.1 1.6.8-lp151.8.3.1

opensuse advisories openSUSE-SU-2024:11005-1openSUSE-SU-2020:0913-1openSUSE-SU-2020:0912-1

  • unbound Alpine 3.10 1.9.1-r8
  • unbound Alpine 3.11 1.9.6-r1
  • unbound Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 1.10.1-r0
  • unbound Alpine 3.9 1.8.3-r4

alpine advisories ALPINE-CVE-2020-12662

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

  • unbound CBL-Mariner 2.0 1.10.0-5

azure linux advisories AZL-6929

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

  • unbound Arch Linux 1.10.1-1

arch linux advisories AVG-1164

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-2020-12662 updated cvss 7.5

unbound: amplification of an incoming query into a large number of queries directed to a target

  • Red Hat Enterprise Linux AppStream (v. 8) unbound 1.7.3-11.el8_2, unbound-libs 1.7.3-11.el8_2, python3-unbound 1.7.3-11.el8_2
    fixed: vendor fix RHSA-2020:2416
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) unbound 1.7.3-9.el8_0, unbound-libs 1.7.3-9.el8_0, python3-unbound 1.7.3-9.el8_0
    fixed: vendor fix RHSA-2020:2418
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) unbound 1.7.3-9.el8_1, unbound-libs 1.7.3-9.el8_1, python3-unbound 1.7.3-9.el8_1
    fixed: vendor fix RHSA-2020:2419
  • Red Hat Enterprise Linux Client (v. 7) unbound 1.6.6-4.el7_8, unbound-libs 1.6.6-4.el7_8 Red Hat Enterprise Linux Client Optional (v. 7) unbound-python 1.6.6-4.el7_8 Red Hat Enterprise Linux ComputeNode (v. 7) unbound 1.6.6-4.el7_8, unbound-libs 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.7) unbound 1.6.6-2.el7_7, unbound-libs 1.6.6-2.el7_7
    fixed: vendor fix RHSA-2020:4181
  • Red Hat Enterprise Linux ComputeNode Optional (v. 7) unbound 1.6.6-4.el7_8, unbound-python 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.7) unbound 1.6.6-2.el7_7, unbound-python 1.6.6-2.el7_7
    fixed: vendor fix RHSA-2020:4181
  • Red Hat Enterprise Linux Desktop (v. 6) unbound 1.4.20-29.el6_10.1, unbound-libs 1.4.20-29.el6_10.1 Red Hat Enterprise Linux Desktop Optional (v. 6) unbound 1.4.20-29.el6_10.1, unbound-python 1.4.20-29.el6_10.1 Red Hat Enterprise Linux Server (v. 6) unbound 1.4.20-29.el6_10.1, unbound-libs 1.4.20-29.el6_10.1
    fixed: vendor fix RHSA-2020:2640
show 9 more
  • Red Hat Enterprise Linux Server (v. 7) unbound 1.6.6-4.el7_8, unbound-libs 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414
  • Red Hat Enterprise Linux Server EUS (v. 7.7) unbound 1.6.6-2.el7_7, unbound-libs 1.6.6-2.el7_7
    fixed: vendor fix RHSA-2020:4181
  • Red Hat Enterprise Linux Server Optional (v. 6) unbound-python 1.4.20-29.el6_10.1
    fixed: vendor fix RHSA-2020:2640
  • Red Hat Enterprise Linux Server Optional (v. 7) unbound-python 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.7) unbound-python 1.6.6-2.el7_7
    fixed: vendor fix RHSA-2020:4181
  • Red Hat Enterprise Linux Workstation (v. 6) unbound 1.4.20-29.el6_10.1, unbound-libs 1.4.20-29.el6_10.1
    fixed: vendor fix RHSA-2020:2640
  • Red Hat Enterprise Linux Workstation (v. 7) unbound 1.6.6-4.el7_8, unbound-libs 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414
  • Red Hat Enterprise Linux Workstation Optional (v. 6) unbound-python 1.4.20-29.el6_10.1
    fixed: vendor fix RHSA-2020:2640
  • Red Hat Enterprise Linux Workstation Optional (v. 7) unbound-python 1.6.6-4.el7_8
    fixed: vendor fix RHSA-2020:2414

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

3.20% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.