Resource exhaustion in CoreDNS - CVE-2026-32936
Published: April 25, 2026
Vulnerability identifier: #VU127723
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-32936
CWE-ID: CWE-400
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 cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the DoH GET request handling path in plugin/pkg/doh/doh.go when processing oversized dns= query parameters in requests to /dns-query. A remote attacker can send repeated oversized DoH GET requests to cause a denial of service.
The requests are rejected only after substantial URL query parsing, unescaping, base64 decoding, and DNS message unpacking work has already occurred.
How to mitigate CVE-2026-32936
Install security update from vendor's website.