CoreDNS is a DNS server written in Go. Prior to 1.14.7, the DNS-over-HTTPS, DNS-over-HTTP/3, DNS-over-QUIC, and DNS-over-gRPC listeners in plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and core/dnsserver/server_grpc.go call dns.Msg.Unpack without the dns.DefaultMsgAcceptFunc request policy used by UDP, TCP, and DNS-over-TLS. An unauthenticated client can send an RFC 2136 UPDATE that the proxy or forward plugin passes unchanged to an update-capable upstream. If that upstream trusts CoreDNS's source address or connection and does not require an attacker-unknown end-to-end TSIG, the request appears to originate from CoreDNS and can add, replace, or delete DNS records, redirect traffic, take over names, alter mail routing, or disrupt the writable zone. This issue is fixed in version 1.14.7.
History

Sat, 19 Sep 2026 23:00:00 +0000

Type Values Removed Values Added
First Time appeared Coredns.io
Coredns.io coredns
Vendors & Products Coredns.io
Coredns.io coredns

Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 17 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-306
References
Metrics threat_severity

None

threat_severity

Important


Wed, 16 Sep 2026 19:00:00 +0000

Type Values Removed Values Added
Description CoreDNS is a DNS server written in Go. Prior to 1.14.7, the DNS-over-HTTPS, DNS-over-HTTP/3, DNS-over-QUIC, and DNS-over-gRPC listeners in plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and core/dnsserver/server_grpc.go call dns.Msg.Unpack without the dns.DefaultMsgAcceptFunc request policy used by UDP, TCP, and DNS-over-TLS. An unauthenticated client can send an RFC 2136 UPDATE that the proxy or forward plugin passes unchanged to an update-capable upstream. If that upstream trusts CoreDNS's source address or connection and does not require an attacker-unknown end-to-end TSIG, the request appears to originate from CoreDNS and can add, replace, or delete DNS records, redirect traffic, take over names, alter mail routing, or disrupt the writable zone. This issue is fixed in version 1.14.7.
Title CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP
Weaknesses CWE-441
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-16T18:39:22.955Z

Updated: 2026-09-17T19:25:42.634Z

Reserved: 2026-09-04T19:17:36.246Z

Link: CVE-2026-86003

cve-icon Vulnrichment

Updated: 2026-09-17T17:06:23.818Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-16T19:17:51.760

Modified: 2026-09-24T21:24:11.250

Link: CVE-2026-86003

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-16T18:39:22Z

Links: CVE-2026-86003 - Bugzilla