OCTOBER 13, 2026
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Case File

CVE-2026-86003

HIGH · CVSS 7.5 EPSS 0.44% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-16 · Last synced 2026-10-13

CyberRota Analysis

AI-Generated

CoreDNS versions prior to 1.14.7 are vulnerable to unauthorized DNS record manipulation due to improper handling of DNS-over-HTTPS, DNS-over-HTTP/3, DNS-over-QUIC, and DNS-over-gRPC requests. An unauthenticated client can exploit this flaw to send malicious updates that may allow them to alter DNS records, potentially leading to traffic redirection, domain takeover, or disruption of services. Organizations using CoreDNS should prioritize upgrading to version 1.14.7 to mitigate these risks.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-86003
Severity
HIGH
CVSS
7.5
EPSS
0.44%

Original NVD 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 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.