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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| coredns | coredns | < 1.14.3 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | coredns | 1.11.4-17 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | coredns-1.13 +1 | No fix yet | — |
| Wolfi rolling | juicefs-1.3 | 1.3.1-r14 | — |
| Wolfi rolling | k8s_gateway | 1.8.0-r1 | — |
| Wolfi rolling | kubernetes-dns-node-cache | 1.26.8-r3 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/coredns/coredns | < 1.14.3 | 1.14.3 | GHSA-63cw-r7xf-jmwr |
Advisories 2
- WID-SEC-2026-1283 CoreDNS: Mehrere Schwachstellen ermöglichen BSI CERT-Bund (WID) · Sep 21, 2026
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026