Improper Authentication in CoreDNS - CVE-2026-33190
Published: April 25, 2026
Vulnerability identifier: #VU127722
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-33190
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: CoreDNS
Affected software:
CoreDNS
CoreDNS
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper authentication in the tsig plugin when handling TSIG-protected requests over DoT, DoH, DoH3, DoQ, or gRPC transports. A remote attacker can send a request with an invalid TSIG to disclose sensitive information.
The issue affects non-plain-DNS transports because TSIG validity is determined from the transport writer status instead of being verified by the plugin itself.
How to mitigate CVE-2026-33190
Install security update from vendor's website.