CVE-2026-86003

CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP

Published: Sep 16, 2026Updated: Sep 17, 2026 Sources: CVE List NVDCWE-441

7.5HIGH

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:HIntegrity

High

A:NAvailability

None

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Weaknesses

CWE-441

Affected Products

coredns

oss-project

corednsOn-prem

Networking Infrastructure / dns-dhcp-ntp

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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References

https://github.com/coredns/coredns/security/advisories/GHSA-9gm5-9rfh-m6vx

github.com

https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9

github.com

https://github.com/coredns/coredns/releases/tag/v1.14.7

github.com

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