CVE-2026-39155

MEDIUM CVSS 3.1: 6.5 EPSS 0.15%
Updated Jul 24, 2026
Knot
Parameter Value
CVSS 6.5 (MEDIUM)
Affected Versions before 3.4.10
Type CWE-345 (Insufficient Verification of Data)
Vendor Knot
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1