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CVE-2026-33190— CoreDNS TSIG authentication bypass on encrypted DNS transports

Quick assessment

Affected
coredns coredns
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

CoreDNS是CoreDNS社区的一个 DNS 服务器。 CoreDNS 1.14.3之前版本存在安全漏洞，该漏洞源于tsig插件信任传输写入器的TsigStatus而非自行验证，可能导致未经身份验证的远程客户端绕过TSIG身份验证。

AI Predicted 9.1 Difficulty: Easy EPSS 0.53% · P42

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
coredns coredns < 1.14.3 affected
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I. Basic Information for CVE-2026-33190

Vulnerability Information
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Vulnerability Title
CoreDNS TSIG authentication bypass on encrypted DNS transports
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
认证算法的不正确实现
Source: CVE Program / CVE List V5
Vulnerability Title
CoreDNS 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
CoreDNS是CoreDNS社区的一个 DNS 服务器。 CoreDNS 1.14.3之前版本存在安全漏洞，该漏洞源于tsig插件信任传输写入器的TsigStatus而非自行验证，可能导致未经身份验证的远程客户端绕过TSIG身份验证。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
coredns coredns < 1.14.3 -

II. Public POCs for CVE-2026-33190

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III. Intelligence Information for CVE-2026-33190

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Vendor Advisories for CVE-2026-33190 (1)

Other References for CVE-2026-33190 (1)

Same Patch Batch · coredns · 2026-05-05 · 5 CVEs total

CVE-2026-32936 CoreDNS DoH GET path missing size validation causes CPU and memory amplification
CVE-2026-32934 CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service
CVE-2026-33489 CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison
CVE-2026-35579 CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports

IV. Related Vulnerabilities

Same product: coredns
Same vendor: coredns
Same weakness: CWE-303

V. Comments for CVE-2026-33190

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