CVE-2026-33190

HIGH
Published May 5, 2026 Modified May 8, 2026 CWE-303

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.

Is your site exposed to CVE-2026-33190?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0008
Probability of exploitation
0.23%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-303 CWE-303

Affected Products

Vendor Product
coredns.io coredns

References

Frequently Asked Questions

What is CVE-2026-33190? +
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. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-33190? +
CVE-2026-33190 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0008, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-33190? +
CVE-2026-33190 affects products from coredns.io, specifically: coredns. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-33190? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-8314

An Incorrect Implementation of Authentication Algorithm and Exposure of Data Element to Wrong Ses-sion vulnerability in the session handling used …
CVE-2025-48994

SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned …
CVE-2024-4332

An authentication bypass vulnerability has been identified in the REST and SOAP API components of Tripwire Enterprise (TE) 9.1.0 when …
CVE-2025-43856

immich is a high performance self-hosted photo and video management solution. Prior to 1.132.0, immich is vulnerable to account hijacking …
CVE-2025-61783

Python Social Auth is a social authentication/registration mechanism. In versions prior to 5.6.0, upon authentication, the user could be associated …
CVE-2025-13390 10.0

The WP Directory Kit plugin for WordPress is vulnerable to authentication bypass in all versions up to, and including, 1.4.4 …

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-33190 — free, no signup required.