CVE-2026-33190Public exploitNetwork attack vector

Authentication bypass via trusted transport TSIG status

Published May 5, 2026 · Updated May 5, 2026

Authentication bypass in CoreDNS before 1.14.3 allows remote attackers to access TSIG-restricted DNS resources over encrypted transports. The tsig plugin trusts each transport writer's TsigStatus(); DoH, DoH3, DoQ, and gRPC return nil unconditionally, while DoT omits TsigSecret. Exposure requires a tsig require all policy on an affected transport; plain DNS over TCP and UDP still rejects invalid signatures.

CVSS severity8.7
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in CoreDNS before 1.14.3 allows remote attackers to access TSIG-restricted DNS resources over encrypted transports. The tsig plugin trusts each transport writer's TsigStatus(); DoH, DoH3, DoQ, and gRPC return nil unconditionally, while DoT omits TsigSecret. Exposure requires a tsig require all policy on an affected transport; plain DNS over TCP and UDP still rejects invalid signatures.

The record

CVE
CVE-2026-33190
Published
May 5, 2026
Updated
May 5, 2026
Vendor
CoreDNS
Product
CoreDNS
Classifications
CWE-303, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 5, 2026CVE publishedPublication date reported by the CVE source.
  2. May 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.14.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CoreDNS · CoreDNSversion=< 1.14.3

Published CVSS scores

8.7GitHub, Inc.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
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-303Incorrect Implementation of Authentication Algorithm
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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