Description
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.
Published: 2026-07-23
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 24 Jul 2026 20:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-345
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 24 Jul 2026 00:45:00 +0000

Type Values Removed Values Added
First Time appeared Knot-dns
Knot-dns knot Dns
Vendors & Products Knot-dns
Knot-dns knot Dns

Thu, 23 Jul 2026 21:45:00 +0000

Type Values Removed Values Added
Description 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.
References

Subscriptions

Knot-dns Knot Dns
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-07-24T19:35:57.930Z

Reserved: 2026-04-06T00:00:00.000Z

Link: CVE-2026-39155

cve-icon Vulnrichment

Updated: 2026-07-24T19:35:36.823Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-24T00:30:07Z

Weaknesses