CVE-2026-39155

knot: 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 na...

CVE-2026-39155 is fixed in knot on 1 platform by DEBIAN-CVE-2026-39155 (version 3.5.4-1), released July 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
6.5
medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0022
12th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
knot · Debian 14 3.5.4-1 DEBIAN-CVE-2026-39155 Jul 25, 2026

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