CVE-2026-82399

CoreDNS: Unauthenticated memory exhaustion in custom transports

Published: Sep 16, 2026Updated: Sep 18, 2026 Sources: CVE List NVDCWE-770

7.5HIGH

Description

CoreDNS is a DNS server written in Go. Prior to 1.14.7, the DNS-over-HTTPS, DNS-over-HTTP/3, DNS-over-QUIC, and DNS-over-gRPC request paths in plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and core/dnsserver/server_grpc.go call dns.Msg.Unpack on attacker-controlled DNS section counts before dns.DefaultMsgAcceptFunc validates the fixed header. An unauthenticated client can use DNS name compression and excessive section counts to amplify allocation before the plugin chain, so plugin-level rate limiting cannot prevent concurrent requests from exhausting memory and terminating CoreDNS. The ordinary UDP and TCP listeners are not affected because they validate the header first. This issue is fixed in version 1.14.7.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:HAvailability

High

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Weaknesses

CWE-770

Affected Products

coredns

oss-project

corednsOn-prem

Networking Infrastructure / dns-dhcp-ntp

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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Attack Graph

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MITRE ATT&CK

1 technique

Impact

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References

https://github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29

github.com

https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9

github.com

https://github.com/coredns/coredns/releases/tag/v1.14.7

github.com

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