TSIG Authentication Bypass in CoreDNS Affects Multiple Transports
CVE-2026-33190

8.7HIGH

Key Information:

Vendor

Coredns

Status
Coredns
Vendor
CVE Published:
5 May 2026

What is CVE-2026-33190?

A vulnerability in CoreDNS allows an unauthenticated remote client to bypass TSIG-based authentication when using non-plain-DNS transports such as DoT, DoH, DoH3, DoQ, and gRPC. This occurs because the tsig plugin improperly trusts the transport writer's TsigStatus() response, which can mistakenly return nil, thereby enabling unauthorized access to restricted resources. The issue has been addressed in version 1.14.3 of CoreDNS.

Affected Version(s)

coredns < 1.14.3

References

https://github.com/coredns/coredns/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/coredns/coredns/releases/tag/v1.14.3
x_refsource_MISC

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.