CVE 8.7 HIGH

CoreDNS TSIG authentication bypass on encrypted DNS transports_CVE-2026-33190

8.7 / 10
HIGH
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

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.

AI Analysis

TSIG authentication bypass on encrypted DNS transports

Basic Information

ID CVE-2026-33190
Source GitHub_M
Published May 5, 2026 at 19:02

Affected Product

Vendor coredns
Product coredns
Version < 1.14.3
Affected Versions coredns coredns < 1.14.3

CWE Classification

AI Assessment

AI Score 8.7 / 10
AI Severity High
Vendor CoreDNS
Product CoreDNS
Version < 1.14.3

References

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