CVE-2020-12663

Name: CVE-2020-12663
Creator: NVD / NIST
Published: 2020-05-19T14:15:11.253+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 3.59%

Last modified Jun 17, 2026

CVE-2020-12663 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Unbound before 1.10.1 has an infinite loop via malformed DNS answers received from upstream servers.. EPSS estimates a 3.59% chance of exploitation in the next 30 days.

Description

Unbound before 1.10.1 has an infinite loop via malformed DNS answers received from upstream servers.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

3.59%

88.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions
Nlnetlabs	Unbound	< 1.10.1
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Opensuse	Leap	15.1
Opensuse	Leap	15.2
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	19.10
Canonical	Ubuntu Linux	20.04
Fedoraproject	Fedora	31
Fedoraproject	Fedora	32

References

http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00067.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00069.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/05/19/5Mailing List, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00017.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F5NFROI2OMCZLYRTCNGHGO3TUD32LCIQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YJ42N2HBZ3DXMSEC56SWIIOFQGOS5M7I/
https://nlnetlabs.nl/downloads/unbound/CVE-2020-12662_2020-12663.txtVendor Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:19.unbound.ascThird Party Advisory
https://usn.ubuntu.com/4374-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4694Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00067.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00069.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/05/19/5Mailing List, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00017.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F5NFROI2OMCZLYRTCNGHGO3TUD32LCIQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YJ42N2HBZ3DXMSEC56SWIIOFQGOS5M7I/
https://nlnetlabs.nl/downloads/unbound/CVE-2020-12662_2020-12663.txtVendor Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:19.unbound.ascThird Party Advisory
https://usn.ubuntu.com/4374-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4694Third Party Advisory

Timeline

Published: May 19, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12663?

Unbound before 1.10.1 has an infinite loop via malformed DNS answers received from upstream servers.

How severe is CVE-2020-12663?

CVE-2020-12663 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.59% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12663?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-12663?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST