High severity · published Sep 16, 2026
CVE-2026-82399
CoreDNS: Unauthenticated memory exhaustion in custom transports
7.5
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 49% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
coredns · coredns
< 1.14.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-82399
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-82399
github.com
https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9
github.com
https://github.com/coredns/coredns/releases/tag/v1.14.7
github.com
https://github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29
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