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CVE-2026-86003— CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP

Quick assessment

Affected
coredns coredns
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

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 d

CVSS 7.5 · High

Affected Version Matrix 1

VendorProduct Version RangeStatus
coredns coredns < 1.14.7 affected
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I. Basic Information for CVE-2026-86003

Vulnerability Information

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Vulnerability Title
CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
未有动机的代理或中间人(混淆代理)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
coredns coredns < 1.14.7 -

II. Public POCs for CVE-2026-86003

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III. Intelligence Information for CVE-2026-86003

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Patches & Fixes for CVE-2026-86003 (1)

Other References for CVE-2026-86003 (2)

IV. Related Vulnerabilities

Same product: coredns
Same vendor: coredns
Same weakness: CWE-441

V. Comments for CVE-2026-86003

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