VYPR
← All advisories
High severity8.7NVD Advisory· Published Jun 12, 2026· Updated Sep 2, 2026

CVE-2026-47691

CVE-2026-47691

Description

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's DnsResolveContext insufficiently validates the bailiwick of NS records, enabling DNS Cache Poisoning. An attacker controlling an authoritative name server for a subdomain can poison the cache for parent domains (like .co.uk). In io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#add method accepts any NS record from the AUTHORITY section as long as the record's name is a suffix of the questionName. Subsequently, the handleWithAdditional method caches the associated A records from the ADDITIONAL section directly into the authoritativeDnsServerCache under the parent domain's key. This bypasses standard bailiwick rules, where a server authoritative for a subdomain should not be trusted to provide authoritative records for its parent. The poisoned cache is then used for all future resolutions under the parent domain's key. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

175

Patches

Vulnerability mechanics

References

22

News mentions

1