What’s Vulnerable › Vulnerabilities

CVE-2020-12663

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-19 · updated 2026-06-17
• Weakness: CWE-835

Description

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

Affected products

• Canonical Ubuntu Linux: 18.04, 19.10, 20.04
• Debian Linux: 9.0, 10.0
• Fedoraproject Fedora: 31, 32
• NLnet Labs Unbound: before 1.10.1 — fixed in 1.10.1
• openSUSE Leap: 15.1, 15.2

How to fix

Upgrade to a fixed version: NLnet Labs Unbound 1.10.1. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00067.html
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00069.html
• http://www.openwall.com/lists/oss-security/2020/05/19/5
• https://lists.debian.org/debian-lts-announce/2021/02/msg00017.html
• 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.txt
• https://security.FreeBSD.org/advisories/FreeBSD-SA-20:19.unbound.asc
• https://usn.ubuntu.com/4374-1/
• https://www.debian.org/security/2020/dsa-4694
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00067.html
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00069.html

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