---
title: "CVE-2026-86003: CoreDNS - Broken Access Control"
description: "CoreDNS < 1.14.7 contains a broken access control vulnerability caused by missing dns.DefaultMsgAcceptFunc policy in DNS-over-HTTPS, HTTP/3, QUIC, and gRPC listeners, letting unauthenticated clients perform unauthorized DNS updates, exploit requires upstream trusting CoreDNS source without end-to-end TSIG."
url: https://panop.io/threat-heartbeat/CVE-2026-86003/
---

# CVE-2026-86003 CoreDNS - Broken Access Control

CoreDNS < 1.14.7 contains a broken access control vulnerability caused by missing dns.DefaultMsgAcceptFunc policy in DNS-over-HTTPS, HTTP/3, QUIC, and gRPC listeners, letting unauthenticated clients perform unauthorized DNS updates, exploit requires upstream trusting CoreDNS source without end-to-end TSIG.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.44% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-86003)

## Details

Type

Broken Access Control

Impact

Broken Access Control, Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Published

16 September 2026

Updated

15 October 2026

Weakness

[CWE-441](https://cwe.mitre.org/data/definitions/441.html)

## Vendor fix

Update to version 1.14.7 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-86003](https://nvd.nist.gov/vuln/detail/CVE-2026-86003)
- [https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9](https://github.com/coredns/coredns/commit/530b0a5ff2ad68cc0421f10dd93568945cc671c9)
- [https://github.com/coredns/coredns/releases/tag/v1.14.7](https://github.com/coredns/coredns/releases/tag/v1.14.7)
- [https://github.com/coredns/coredns/security/advisories/GHSA-9gm5-9rfh-m6vx](https://github.com/coredns/coredns/security/advisories/GHSA-9gm5-9rfh-m6vx)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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