---
id: CVE-2026-82399
title: CoreDNS is a DNS server written in Go
summary: >-
  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 d…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
  - CWE-1050
vendor: coredns
product: coredns
affected:
  - coredns < 1.14.7
patched:
  - github.com/coredns/coredns 1.14.7
published: '2026-09-16'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:16:28.120'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82399'
references:
  - url: >-
      https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/releases/tag/v1.14.7'
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29'
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/security/advisories/GHSA-mrg3-qvqr-jw29'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82399.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-82399'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2535609'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-82399'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82399'
  - url: 'https://github.com/advisories/GHSA-mrg3-qvqr-jw29'
  - url: 'https://github.com/coredns/coredns'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - ghsa
  - go
  - osv
  - exploit-available
epss: 0.00609
epssPercentile: 0.46836
aliases:
  - GHSA-mrg3-qvqr-jw29
ecosystem: go
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T18:18:56.250464Z'
ingestedAt: '2026-09-16T19:02:30.728Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-82399)

Affected packages:

- `github.com/coredns/coredns <= 1.14.6`

Patched in:

- `github.com/coredns/coredns 1.14.7`

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · updated 2026-09-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82399.json)