Bug 2439531 (CVE-2026-26076)

Summary: CVE-2026-26076 ntpd-rs: ntpd-rs: Denial of Service via malformed NTS packets requesting excessive cookies
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A denial of service flaw has been discovered in ntpd-rs. When Network Time Security (NTS) is enabled on an ntpd-rs server, a remote attacker can create malformed NTS packets that take significantly more effort for the server to respond to by requesting a large number of cookies. This can lead to degraded server performance even when a server could otherwise handle the load.
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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: 2439600, 2439601, 2439602    
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Description OSIDB Bzimport 2026-02-12 22:01:17 UTC
ntpd-rs is a full-featured implementation of the Network Time Protocol. Prior to 1.7.1, an attacker can remotely induce moderate increases (2-4 times above normal) in cpu usage. When having NTS enabled on an ntpd-rs server, an attacker can create malformed NTS packets that take significantly more effort for the server to respond to by requesting a large number of cookies. This can lead to degraded server performance even when a server could otherwise handle the load. This vulnerability is fixed in 1.7.1.