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.
Published: 2026-09-16
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

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

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

Link: CVE-2026-86003

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-86003

cve-icon Redhat

Severity : Important

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

Links: CVE-2026-86003 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-306

    Missing Authentication for Critical Function

  • CWE-441

    Unintended Proxy or Intermediary ('Confused Deputy')