CoreDNS up to 1.14.6 DNS-over-HTTPS Listener plugin/pkg/doh/doh.go dns.Msg.Unpack privileges management

Summaryinfo

A vulnerability was found in CoreDNS up to 1.14.6. It has been classified as problematic. Affected is the function dns.Msg.Unpack of the file plugin/pkg/doh/doh.go of the component DNS-over-HTTPS Listener. This manipulation causes privileges management. This vulnerability is registered as CVE-2026-86003. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in CoreDNS up to 1.14.6 and classified as problematic. Affected by this vulnerability is the function dns.Msg.Unpack of the file plugin/pkg/doh/doh.go of the component DNS-over-HTTPS Listener. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-86003 since 09/04/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 1.14.7 eliminates this vulnerability.

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Productinfo

Name

• CoreDNS

Version

• 1.14.0
• 1.14.1
• 1.14.2
• 1.14.3
• 1.14.4
• 1.14.5
• 1.14.6

Website

• Product: https://github.com/coredns/coredns/

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