Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port

Summary Netty's DNS resolver uses a predictable PRNG for generating DNS transaction IDs and defaults to a static UDP source port. This combination reduces the entropy of DNS queries, enabling DNS Cache Poisoning Kaminsky attack. Details Two factors contribute to this vulnerability in...

PT-2026-47610

Name of the Vulnerable Software and Affected Versions Netty versions prior to 4.1.135.Final Netty versions prior to 4.2.15.Final Description Netty's DnsResolveContext fails to validate the origin bailiwick of CNAME records in DNS responses. In the buildAliasMap function within...

PT-2026-47551

Summary 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. Details In...

PT-2026-47554

Summary Netty's DnsResolveContext fails to validate the origin bailiwick of CNAME records in DNS responses. Details In io.netty.resolver.dns.DnsResolveContextbuildAliasMap, the resolver processes the ANSWER section of a DNS response and blindly caches all CNAME records it finds. According to...

PT-2026-47609

Name of the Vulnerable Software and Affected Versions Netty versions prior to 4.1.135.Final Netty versions prior to 4.2.15.Final Description The DNS resolver in the io.netty.resolver.dns module uses a predictable Pseudo-Random Number Generator PRNG for generating DNS transaction IDs and defaults ...