CVE-2026-33190 (GCVE-0-2026-33190)

Vulnerability from cvelistv5 – Published: 2026-05-05 19:02 – Updated: 2026-05-06 12:47
VLAI
Title
CoreDNS TSIG authentication bypass on encrypted DNS transports
Summary
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.
Severity
8.7 (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
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-06 12:46 UTC
CWE
  • CWE-303 - Incorrect Implementation of Authentication Algorithm
Assigner
References
Impacted products
Vendor Product Version CPE status
coredns coredns Affected: < 1.14.3
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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