CVE-2019-19331 Denial of service in knot-resolver

What is CVE-2019-19331?

CVE-2019-19331 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 16 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS replies with very many resource records might be processed very inefficiently, in extreme cases taking even several CPU seconds for each such uncached message. For example, a few thousand A records can be squashed into one DNS message (limit is 64kB).

Weakness: CWE-404, CWE-407

Which versions are affected by CVE-2019-19331?

It affects 2 products.

Products include Debian Debian Linux, Nic Knot Resolver.

How do I fix CVE-2019-19331?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2019-19331 being exploited?

There is no known exploitation of CVE-2019-19331 in the wild and no public exploit code.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2019-19331, GHSA-9f7v-8m4p-pv76, UBUNTU-CVE-2019-19331.