Vulnerability · Published May 5, 2026 · Assigned by GitHub_M
CVE-2026-32936CoreDNS DoH GET path missing size validation causes CPU and memory amplification
High 8.7
In plain English
A high-severity uncontrolled resource consumption in coredns from coredns. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/coredns/coredns | 1.14.3 | GHSA-63cw-r7xf-jmwr |
| Go | github.com/coredns/coredns | 1.14.3 | GO-2026-5164 |
Affected products (as reported)
Weakness: CWE-400 · Vector: 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
References
- https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr x_refsource_CONFIRM
- https://github.com/coredns/coredns/releases/tag/v1.14.3 x_refsource_MISC