Bug 2520879

Summary: CVE-2026-39155 knot: Knot DNS: Denial of Service due to incorrect NSEC owner name computation [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Ganesh <gnaik>
Component: knotAssignee: Paul Wouters <paul.wouters>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: epel10CC: dns-sig, jruzicka.pkg, paul.wouters, pspacek
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["70637b4e-e841-4a18-802a-89faadc25dbb"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2506619    

Description Ganesh 2026-08-21 03:16:04 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.