CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the tsig plugin can be bypassed on non-plain-DNS transports (DoT, DoH, DoH3, DoQ, and gRPC) because it trusts the transport writer's TsigStatus() instead of performing verification itself. The DoH and DoH3 writer's TsigStatus() always returns nil, the DoT server does not set TsigSecret on the dns.Server, and the DoQ and gRPC writers also unconditionally return nil. This allows an unauthenticated remote client to bypass TSIG-based authentication and access resources intended to be restricted behind a tsig require all policy. Plain DNS over TCP and UDP are not affected. This issue has been fixed in version 1.14.3.

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Source ID Title
Github GHSA Github GHSA GHSA-qhmp-q7xh-99rh CoreDNS has TSIG authentication bypass on DoT, DoH, DoH3, DoQ, and gRPC
Fixes

Solution

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Workaround

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History

Tue, 05 May 2026 21:45:00 +0000

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

Tue, 05 May 2026 19:30:00 +0000

Type Values Removed Values Added
Description CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the tsig plugin can be bypassed on non-plain-DNS transports (DoT, DoH, DoH3, DoQ, and gRPC) because it trusts the transport writer's TsigStatus() instead of performing verification itself. The DoH and DoH3 writer's TsigStatus() always returns nil, the DoT server does not set TsigSecret on the dns.Server, and the DoQ and gRPC writers also unconditionally return nil. This allows an unauthenticated remote client to bypass TSIG-based authentication and access resources intended to be restricted behind a tsig require all policy. Plain DNS over TCP and UDP are not affected. This issue has been fixed in version 1.14.3.
Title CoreDNS TSIG authentication bypass on encrypted DNS transports
Weaknesses CWE-303
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-05T19:02:55.374Z

Reserved: 2026-03-17T22:16:36.721Z

Link: CVE-2026-33190

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-05T20:16:36.167

Modified: 2026-05-05T20:16:36.167

Link: CVE-2026-33190

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-05T21:30:05Z

Weaknesses