CVE-2019-19331: cz.nic knot-resolver Inefficient Algorithmic Complexity
Vulnerability summary
CVE-2019-19331 is a high (CVSS 7.5) Inefficient Algorithmic Complexity vulnerability in cz.nic knot-resolver. EPSS estimates a 2.11% chance of exploitation in the next 30 days, higher than 81.4% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 2 · Related 1Timeline
- 16-12-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
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).
CVSS metrics
7 scores · 4 sources · 3 versions- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
2.11%
Chance of exploitation in the next 30 days
Percentile
81%
Versus all other CVEs
30-day change
-0.06 pp
From 2.17% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (bugzilla.redhat.com)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
- CWE-404Improper Resource Shutdown or ReleaseThe product does not release or incorrectly releases a resource before it is made available for re-use.
Affected systems
Debian2 products
- knot-resolver< 5.0.1-1
- debian_linuxEOL10.0
Cz.nic1 product
- knot-resolver4.3.0
Nic1 product
- knot_resolver< 4.3.0
Ubuntu1 product
- knot-resolverAll versions (No fix recorded) | < 3.2.1-3ubuntu2.2
4 vendors · 5 products
