{"cve":"CVE-2026-47691","nvd":{"published":"2026-06-12T16:16:30.310","modified":"2026-09-18T13:18:28.497","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N","score":10.0},"cwes":["CWE-345","CWE-346"],"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"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-47691","score":0.00372,"percentile":0.3114,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-5pvg-856g-cp85","url":"https://osv.dev/vulnerability/GHSA-5pvg-856g-cp85","summary":"Netty has Insufficient Bailiwick Validation for NS Records","modified":"2026-09-18T15:45:05.623298702Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-resolver-dns","purl":"pkg:maven/io.netty/netty-resolver-dns","ranges":[">=4.2.0.Final <4.2.15.Final"],"fixed":["4.2.15.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-resolver-dns","purl":"pkg:maven/io.netty/netty-resolver-dns","ranges":["<4.1.135.Final"],"fixed":["4.1.135.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}