CVE-2020-12663

unbound: infinite loop via malformed DNS answers received from upstream servers

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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

Unbound versiones anteriores a 1.10.1, presenta un bucle infinito mediante respuestas DNS malformadas recibidas desde servidores aguas arriba.

A flaw was found in unbound in versions prior to 1.10.1. An infinite loop can be created when malformed DNS answers are received from upstream servers. The highest threat from this vulnerability is to system availability.

An update that fixes three vulnerabilities is now available. This update for unbound fixes the following issues. Fixed an issue where unbound could have been tricked into amplifying an incoming query into a large number of queries directed to a target. Fixed an issue where malformed answers from upstream name servers could have been used to make unbound unresponsive. Fixed a vulnerability in the IPSec module which could have allowed code execution after receiving a special crafted answer. This update was imported from the SUSE:SLE-15-SP1:Update update project.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-05-05 CVE Reserved
2020-05-19 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

CAPEC

References (12)

URL	Tag	Source
https://lists.debian.org/debian-lts-announce/2021/02/msg00017.html	Mailing List

URL	Date	SRC

URL	Date	SRC
http://www.openwall.com/lists/oss-security/2020/05/19/5	2023-11-07

URL	Date	SRC
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00067.html	2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00069.html	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F5NFROI2OMCZLYRTCNGHGO3TUD32LCIQ	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YJ42N2HBZ3DXMSEC56SWIIOFQGOS5M7I	2023-11-07
https://nlnetlabs.nl/downloads/unbound/CVE-2020-12662_2020-12663.txt	2023-11-07
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:19.unbound.asc	2023-11-07
https://usn.ubuntu.com/4374-1	2023-11-07
https://www.debian.org/security/2020/dsa-4694	2023-11-07
https://access.redhat.com/security/cve/CVE-2020-12663	2020-10-06
https://bugzilla.redhat.com/show_bug.cgi?id=1837604	2020-10-06

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Nlnetlabs Search vendor "Nlnetlabs"		Unbound Search vendor "Nlnetlabs" for product "Unbound"				< 1.10.1 Search vendor "Nlnetlabs" for product "Unbound" and version " < 1.10.1"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Opensuse Search vendor "Opensuse"		Leap Search vendor "Opensuse" for product "Leap"				15.1 Search vendor "Opensuse" for product "Leap" and version "15.1"		-		Affected
Opensuse Search vendor "Opensuse"		Leap Search vendor "Opensuse" for product "Leap"				15.2 Search vendor "Opensuse" for product "Leap" and version "15.2"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				18.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "18.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				19.10 Search vendor "Canonical" for product "Ubuntu Linux" and version "19.10"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				20.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "20.04"		lts		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				31 Search vendor "Fedoraproject" for product "Fedora" and version "31"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected