CVE catalog

CVE-2026-39155

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Jul 23, 2026, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 0.22% · Oct 25, 2026

Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	knot	sid	`3.5.8-1`	fixed
Debian	knot	forky	`3.5.8-1`	fixed
Debian	knot	trixie	`3.4.6-2`	vulnerable
Debian	knot	bookworm	`3.2.6-1`	vulnerable
Ubuntu	knot	16.04	`2.0.0-1`	vulnerable
Ubuntu	knot	16.04	`2.0.1-4`	vulnerable
Ubuntu	knot	16.04	`2.0.1-4build1`	vulnerable
Ubuntu	knot	16.04	`2.0.2-1`	vulnerable
Ubuntu	knot	16.04	`2.0.2-1build1`	vulnerable
Ubuntu	knot	16.04	`2.1.0~rc1-52-gd80ce77-1`	vulnerable
Ubuntu	knot	16.04	`2.1.0~rc1-55-gf227348-1`	vulnerable
Ubuntu	knot	16.04	`2.1.0-2`	vulnerable
Ubuntu	knot	16.04	`2.1.0-3`	vulnerable
Ubuntu	knot	16.04	`2.1.1-1`	vulnerable
Ubuntu	knot	16.04	`2.1.1-1build1`	vulnerable
Ubuntu	knot	18.04	`2.5.3-3`	vulnerable
Ubuntu	knot	18.04	`2.6.0-1`	vulnerable
Ubuntu	knot	18.04	`2.6.1-2`	vulnerable
Ubuntu	knot	18.04	`2.6.3-1`	vulnerable
Ubuntu	knot	18.04	`2.6.4-1`	vulnerable
Ubuntu	knot	18.04	`2.6.5-1`	vulnerable
Ubuntu	knot	18.04	`2.6.5-3`	vulnerable
Ubuntu	knot	20.04	`2.7.6-2`	vulnerable
Ubuntu	knot	20.04	`2.7.8-1`	vulnerable
Ubuntu	knot	22.04	`3.0.5-1ubuntu1`	vulnerable
Ubuntu	knot	22.04	`3.1.4-1ubuntu1`	vulnerable
Ubuntu	knot	22.04	`3.1.5-1ubuntu1`	vulnerable
Ubuntu	knot	22.04	`3.1.6-1ubuntu1`	vulnerable
Ubuntu	knot	24.04	`3.2.9-1`	vulnerable
Ubuntu	knot	24.04	`3.3.2-1`	vulnerable
Ubuntu	knot	24.04	`3.3.3-1`	vulnerable
Ubuntu	knot	24.04	`3.3.3-2`	vulnerable
Ubuntu	knot	24.04	`3.3.4-1`	vulnerable
Ubuntu	knot	24.04	`3.3.4-1.1build1`	vulnerable
Ubuntu	knot	24.04	`3.3.4-1.1build2`	vulnerable
Ubuntu	knot	26.04	`3.4.6-2`	vulnerable
Ubuntu	knot	26.04	`3.5.1-1`	vulnerable
Ubuntu	knot	26.04	`3.5.2-1`	vulnerable
Ubuntu	knot	26.04	`3.5.3-1`	vulnerable
Ubuntu	knot	26.04	`3.5.3-2`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	knot	source	sid	`3.5.4-1`	not yet assigned	Not reported	Not reported
Debian	knot	source	forky	`3.5.4-1`	not yet assigned	Not reported	Not reported
Debian	knot	source	trixie	`(unfixed)`	not yet assigned	Not reported	Not reported
Debian	knot	source	bookworm	`(unfixed)`	not yet assigned	Not reported	Not reported

Notes

[trixie] knot: Minor issue [bookworm] knot: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[knot]Affected
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-dnssecutils]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-dnsutils]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-doc]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · all · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · all · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-host]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-module-dnstap]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[knot-module-geoip]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[libdnssec9]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[libknot13]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[libknot-dev]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[libzscanner4]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · amd64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · arm64 · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
[python3-libknot]Affected
Source package: [knot]
Details (2)
- 3.2.6-1 · all · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12
- 3.2.6-1 · all · bookworm
  Affected
  nvd · knot · debian · bookworm; nvd · knot · debian · 12

[Debian 13 (Trixie)]

[knot]Affected
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13
[knot-dnssecutils]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13
[knot-dnsutils]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13
[knot-doc]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · all · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · all · trixie
  Affected
  nvd · knot · debian · 13
[knot-exporter]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · all · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · all · trixie
  Affected
  nvd · knot · debian · 13
[knot-host]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13
[knot-module-dnstap]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13
[knot-module-geoip]Affected
Source package: [knot]
Details (2)
- 3.4.6-2 · amd64 · trixie
  Affected
  nvd · knot · debian · 13
- 3.4.6-2 · arm64 · trixie
  Affected
  nvd · knot · debian · 13

Next results

Observed: Oct 23, 2026, 9:43:33 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]