Resource exhaustion in Coredns
CVE-2026-32936
CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-HTTPS (DoH) GET path accepts oversized dns= query parameter values and performs URL query parsing, base64 decoding, and DNS message unpacking before rejecting the request. Unlike the POST path, which applies a bounded read via http.MaxBytesReader limited to 65536 bytes, the GET path has no equivalent size validation before expensive processing. A remote, unauthenticated attacker can repeatedly send oversized DoH GET requests to force high CPU usage, large transient memory allocations, and elevated garbage-collection pressure, leading to denial of service. This issue has been fixed in version 1.14.3.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.006 · change: -0.001
Affected products
- Coredns — versions < 1.14.3
- Coredns.io Coredns
Weakness classification (CWE)
References
- github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr (Exploit, Mitigation, Vendor Advisory)
- github.com/coredns/coredns/releases/tag/v1.14.3 (Release Notes)
Frequently asked questions
- What is CVE-2026-32936?
- CVE-2026-32936 is a high-severity vulnerability in Coredns, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-05-05.
- How severe is CVE-2026-32936?
- High severity. CVSS v3 base score is 7.5 out of 10.