Vulnerability · Published Sep 16, 2026 · Assigned by GitHub_M

CVE-2026-82399CoreDNS: Unauthenticated memory exhaustion in custom transports

High 7.5

In plain English

A high-severity resource allocation without limits in coredns from coredns. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 50.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/coredns/coredns	1.14.7	GHSA-mrg3-qvqr-jw29
Go	github.com/coredns/coredns	1.14.7	GO-2026-6507

Affected products (as reported)

Vendor	Product	Versions
coredns	coredns	< 1.14.7

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29 x_refsource_CONFIRM
https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9 x_refsource_MISC
https://github.com/coredns/coredns/releases/tag/v1.14.7 x_refsource_MISC