---
id: CVE-2026-86003
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 listeners in
  plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and
  core/dnsserver/server_grpc.go call dns.M…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-441
  - CWE-306
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: '2026-09-24T21:24:11.250'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86003'
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-9gm5-9rfh-m6vx'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86003.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-86003'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2535596'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-86003'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86003'
  - url: 'https://github.com/coredns/coredns'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - osv
  - go
epss: 0.00436
epssPercentile: 0.35223
aliases:
  - GHSA-9gm5-9rfh-m6vx
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-17T17:06:22.830359Z'
ingestedAt: '2026-09-16T19:02:30.727Z'
---

## 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 listeners in plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and core/dnsserver/server_grpc.go call dns.Msg.Unpack without the dns.DefaultMsgAcceptFunc request policy used by UDP, TCP, and DNS-over-TLS. An unauthenticated client can send an RFC 2136 UPDATE that the proxy or forward plugin passes unchanged to an update-capable upstream. If that upstream trusts CoreDNS's source address or connection and does not require an attacker-unknown end-to-end TSIG, the request appears to originate from CoreDNS and can add, replace, or delete DNS records, redirect traffic, take over names, alter mail routing, or disrupt the writable zone. 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-2026-86003)

Affected packages:

- `github.com/coredns/coredns < 1.14.7`

Patched in:

- `github.com/coredns/coredns 1.14.7`

Source: https://osv.dev/vulnerability/GHSA-9gm5-9rfh-m6vx

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86003.json)