CVE-2026-19401
Description
A flaw was found in NSD. A remote attacker can crash an NSD server child by sending a specially crafted message containing a specific number of DNS Cookie options. This continuous crashing can severely hamper or deny DNS service, leading to a denial of service (DoS) condition. This vulnerability primarily affects debugging or non-release build types of NSD.
Statement
This vulnerability is evaluated as an Important impact issue for environments deploying NSD, as unauthenticated remote network traffic can disrupt name resolution availability. However, NSD is not packaged or supported within core Red Hat Enterprise Linux products and is only distributed through community channels such as EPEL. Additionally, standard production packages compiled without debugging assertions enabled do not trigger this abnormal termination under typical operational conditions.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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