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

September 17, 2026

CoreDNS parses attacker-controlled DNS section counts before validating them on DNS-over-HTTPS (DoH and DoH3), DNS-over-QUIC (DoQ), and DNS-over-gRPC listeners. An unauthenticated client can use DNS name compression to make one 65,533-byte request allocate more than 10 MiB while it is unpacked. Concurrent requests can exhaust memory and terminate CoreDNS.

References

github.com/advisories/GHSA-mrg3-qvqr-jw29
github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9
github.com/coredns/coredns/releases/tag/v1.14.7
github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29
nvd.nist.gov/vuln/detail/CVE-2026-82399

Code Behaviors & Features

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