Description

A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries to upstream name servers, i.e., at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options is used. Resolvers supporting ECS need to segregate outgoing queries to accommodate for different outgoing ECS information. This re-opens up resolvers to a birthday paradox attack (Rebirthday Attack) that tries to match the DNS transaction ID in order to cache non-ECS poisonous replies.

INFO

Published Date :

2025-07-16T14:38:22.738Z

Last Modified :

2025-07-16T15:42:18.657Z

Source :

NLnet Labs
AFFECTED PRODUCTS

The following products are affected by CVE-2025-5994 vulnerability.

No data.

REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2025-5994.

CVSS Vulnerability Scoring System

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Detailed values of each vector for above chart.
Attack Vector
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User Interaction
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Integrity Impact
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