CVE-2026-33190
CoreDNS TSIG authentication bypass on encrypted DNS transports
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.
INFO
Published Date :
May 5, 2026, 8:16 p.m.
Last Modified :
July 24, 2026, 11:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update CoreDNS to version 1.14.3 or later.
- Apply vendor patches if available.
- Verify TSIG verification is enforced.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33190.
| URL | Resource |
|---|---|
| https://github.com/coredns/coredns/releases/tag/v1.14.3 | Release Notes |
| https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh | Exploit Vendor Advisory |
| https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33190 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33190
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33190 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33190 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Changed Translation Title: CoreDNS, Description: CoreDNS es un servidor DNS que encadena plugins. En versiones anteriores a la 1.14.3, el plugin tsig puede ser eludido en transportes que no son DNS plano (DoT, DoH, DoH3, DoQ y gRPC) porque confía en el TsigStatus() del escritor del transporte en lugar de realizar la verificación por sí mismo. El TsigStatus() del escritor de DoH y DoH3 siempre devuelve nil, el servidor DoT no establece TsigSecret en el dns.Server, y los escritores de DoQ y gRPC también devuelven nil incondicionalmente. Esto permite a un cliente remoto no autenticado eludir la autenticación basada en TSIG y acceder a recursos destinados a ser restringidos detrás de una política tsig require all. DNS plano sobre TCP y UDP no se ven afectados. Este problema ha sido solucionado en la versión 1.14.3. Title: CoreDNS, Description: CoreDNS es un servidor DNS que encadena plugins. En versiones anteriores a la 1.14.3, el plugin tsig puede ser eludido en transportes que no son DNS plano (DoT, DoH, DoH3, DoQ y gRPC) porque confía en el TsigStatus() del escritor del transporte en lugar de realizar la verificación por sí mismo. El TsigStatus() del escritor de DoH y DoH3 siempre devuelve nil, el servidor DoT no establece TsigSecret en el dns.Server, y los escritores de DoQ y gRPC también devuelven nil incondicionalmente. Esto permite a un cliente remoto no autenticado eludir la autenticación basada en TSIG y acceder a recursos destinados a ser restringidos detrás de una política tsig require all. DNS plano sobre TCP y UDP no se ven afectados. Este problema ha sido solucionado en la versión 1.14.3. -
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: CoreDNS, Description: CoreDNS es un servidor DNS que encadena plugins. En versiones anteriores a la 1.14.3, el plugin tsig puede ser eludido en transportes que no son DNS plano (DoT, DoH, DoH3, DoQ y gRPC) porque confía en el TsigStatus() del escritor del transporte en lugar de realizar la verificación por sí mismo. El TsigStatus() del escritor de DoH y DoH3 siempre devuelve nil, el servidor DoT no establece TsigSecret en el dns.Server, y los escritores de DoQ y gRPC también devuelven nil incondicionalmente. Esto permite a un cliente remoto no autenticado eludir la autenticación basada en TSIG y acceder a recursos destinados a ser restringidos detrás de una política tsig require all. DNS plano sobre TCP y UDP no se ven afectados. Este problema ha sido solucionado en la versión 1.14.3. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'coredns', 'product': 'coredns', 'versions': [{'status': 'affected', 'version': '< 1.14.3'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-33190', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-06T12:46:45.291268Z'} -
Initial Analysis by [email protected]
May. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:* versions up to (excluding) 1.14.3 Added Reference Type GitHub, Inc.: https://github.com/coredns/coredns/releases/tag/v1.14.3 Types: Release Notes Added Reference Type CISA-ADP: https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 06, 2026
Action Type Old Value New Value Added Reference https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh -
New CVE Received by [email protected]
May. 05, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-303 Added Reference https://github.com/coredns/coredns/releases/tag/v1.14.3 Added Reference https://github.com/coredns/coredns/security/advisories/GHSA-qhmp-q7xh-99rh