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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-86003
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 19:17:51 UTC
Updated2026-09-16 19:17:51 UTC
DescriptionCoreDNS 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Problem Types: CWE-441 | CWE-441 CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Coredns Coredns affected < 1.14.7 Not specified

References

ReferenceSourceLinkTags
github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9 [email protected] github.com
github.com/coredns/coredns/security/advisories/GHSA-9gm5-9rfh-m6vx [email protected] github.com
github.com/coredns/coredns/releases/tag/v1.14.7 [email protected] github.com
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