CVE-2026-39155

State: Published
Severity: 6.5 Medium
Published: Jul 23, 2026
Updated: Jul 24, 2026
Reserved: Apr 6, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

CWE-345 Insufficient Verification of Data Authenticity

Affected Products

Product	Versions
n/an/a	n/aAffected

References

https://www.knot-dns.cz/2026-04-01-version-3410.html
https://www.knot-dns.cz/2026-04-02-version-354.html

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.