CoreDNS DoH GET path missing size validation causes CPU and memory amplification
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-32936
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 17:21 UTC · Revision 1
Source evidence
CoreDNS DoH GET path missing size validation causes CPU and memory amplification
core-osv · Original sourcePublished 5 May 2026, 19:07 UTC
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.
osv:CVE-2026-32936
Complete source record
{
"id": "e69ba6afd43626d80315b8cdc4c5e4e1d1e2964f23e973b95cadae2c1a90256e",
"url": "https://osv.dev/vulnerability/CVE-2026-32936",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CoreDNS DoH GET path missing size validation causes CPU and memory amplification",
"summary": "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.",
"evidence": "osv:CVE-2026-32936",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-32936",
"aliases": [
"CVE-2026-32936",
"GHSA-63cw-r7xf-jmwr",
"GO-2026-5164"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
}
],
"affected": [
{
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"type": "GIT",
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"source": "REFERENCES_TAG",
"original_tag": "v1.14.3"
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{
"cpe": "cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*",
"range": [
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-32936.json"
}
}
],
"modified": "2026-10-28T02:30:21.364332575Z",
"provider": "osv",
"references": [
"https://github.com/coredns/coredns/releases/tag/v1.14.3",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32936.json",
"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr",
"https://nvd.nist.gov/vuln/detail/CVE-2026-32936"
],
"provider_metadata": {
"cwe_ids": [
"CWE-400"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32936.json"
}
},
"related_cves": [
{
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"evidence": "/id"
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"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 487677,
"published_at": "2026-05-05T19:07:51.926+00:00"
}