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CVE-2026-33190

CoreDNS TSIG authentication bypass on encrypted DNS transports

Published: May 5, 2026Updated: Jul 24, 2026 Sources: CVE List NVDCWE-303
7.5HIGH
NVD MITRE
EPSS Score
0.4%
Top 69.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-303

Affected Products

coredns.io
oss-projectaka coredns
corednsOn-prem
Networking Infrastructure / dns-dhcp-ntp
and 1 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-33190?We can run the check for you — a free external exposure review, no install. Check my exposure

References

https://github.com/coredns/coredns/releases/tag/v1.14.3
github.com
https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh
github.com

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