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, Nettys 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 records 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 domains 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 domains key. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Weakness
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Netty | Netty | * | 4.1.135 (excluding) |
| Netty | Netty | 4.2.0 (including) | 4.2.15 (excluding) |
| Red Hat Build of Apache Camel 3.33 for Quarkus 3.33.2.SP1 | RedHat | netty-resolver-dns | * |
| Red Hat build of Quarkus 3.27.4.SP1 | RedHat | netty-resolver-dns | * |
| Red Hat build of Quarkus 3.33.2.SP1 | RedHat | netty-resolver-dns | * |
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/111.html
- https://cwe.mitre.org/data/definitions/141.html
- https://cwe.mitre.org/data/definitions/142.html
- https://cwe.mitre.org/data/definitions/148.html
- https://cwe.mitre.org/data/definitions/218.html
- https://cwe.mitre.org/data/definitions/384.html
- https://cwe.mitre.org/data/definitions/385.html
- https://cwe.mitre.org/data/definitions/386.html
- https://cwe.mitre.org/data/definitions/387.html
- https://cwe.mitre.org/data/definitions/388.html
- https://cwe.mitre.org/data/definitions/665.html
- https://cwe.mitre.org/data/definitions/701.html
References
- https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
- https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
- https://github.com/netty/netty/security/advisories/GHSA-5pvg-856g-cp85
- https://access.redhat.com/errata/RHSA-2026:26017
- https://access.redhat.com/errata/RHSA-2026:26018
- https://access.redhat.com/errata/RHSA-2026:26586
- https://access.redhat.com/security/cve/CVE-2026-47691
- https://bugzilla.redhat.com/show_bug.cgi?id=2488439
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47691.json