7.5

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

Awaiting analysis
AliasesCGA-38m2-r43r-8j7jCGA-7485-5wgh-vxqqCGA-7ghf-g4g8-8vff
Published 16-09-2026Last modified 17-09-2026

Vulnerability summary

CVE-2026-86003 is a high (CVSS 7.5) Unintended Proxy or Intermediary vulnerability in coredns. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.9% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.44%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 16-09-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.44% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard21 products
  • eks-distro-coredns-1.31< 1.31.47-r12
  • eks-distro-coredns-1.32< 1.32.40-r9
  • eks-distro-coredns-1.33< 1.33.30-r9
  • eks-distro-coredns-1.34< 1.34.21-r9
  • eks-distro-coredns-1.35< 1.35.12-r9
Wolfi3 products
  • juicefs-1.3< 1.3.3-r8
  • k8s_gateway< 1.8.2-r11
  • kubernetes-dns-node-cache< 1.26.8-r20
Coredns1 product
Github.com/coredns1 product
  • coredns< 1.14.7

4 vendors · 26 products

References

6 links