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TI-2026-56816 Aliases CVE-2026-82399GHSA-mrg3-qvqr-jw29

CoreDNS: Unauthenticated memory exhaustion in custom transports

Priority HIGH 72CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-770.

Summary

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 request paths in plugin/pkg/doh/doh.go, core/dnsserver/server_quic.go, and core/dnsserver/server_grpc.go call dns.Msg.Unpack on attacker-controlled DNS section counts before dns.DefaultMsgAcceptFunc validates the fixed header. An unauthenticated client can use DNS name compression and excessive section counts to amplify allocation before the plugin chain, so plugin-level rate limiting cannot prevent concurrent requests from exhausting memory and terminating CoreDNS. The ordinary UDP and TCP listeners are not affected because they validate the header first. This issue is fixed in version 1.14.7.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00609 49th percentileScored 2026-11-07
Fix Partial coredns (coredns): 1.14.7github.com/coredns/coredns (Go): 1.14.7Red Hat: 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
corednscorednsbefore 1.14.71.14.7Patch availableCNA
—github.com/coredns/coredns (Go)before 1.14.71.14.7Patch availableGHSA-mrg3-qvqr-jw29
  • coredns Vendorcoredns Affected before 1.14.7 Fixed in 1.14.7 Patch available CNA
  • github.com/coredns/coredns (Go) Vendor— Affected before 1.14.7 Fixed in 1.14.7 Patch available GHSA-mrg3-qvqr-jw29

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*——coredns
  • cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:* Versions — — ·coredns

Remediation

  • Fix · CNA coredns (coredns) Fixed in 1.14.7
  • Fix · GHSA-mrg3-qvqr-jw29 github.com/coredns/coredns (Go) Fixed in 1.14.7 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Connectivity Link 1AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Not affected: 2 products
  • Red Hat Advanced Cluster Management for Kubernetes 2
  • Red Hat OpenShift Container Platform 4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-82399
  2. 2026-10-03 Alias added: GHSA-mrg3-qvqr-jw29
  3. 2026-10-15 Affected versions changed · Red Hat
  4. 2026-10-30 Affected versions changed · Red Hat

References

Advisory 1

Other 4

  • TI-2026-25615 CoreDNS TSIG authentication bypass on encrypted DNS transports CVSS 4.0HIGH 8.7
  • TI-2026-25384 CoreDNS DoH GET path missing size validation causes CPU and memory amplification CVSS 4.0HIGH 8.7
  • TI-2026-25382 CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service CVSS 4.0HIGH 8.7
  • TI-2026-27682 CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports CVSS 4.0HIGH 8.2
  • TI-2026-25885 CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison CVSS 4.0HIGH 8.2
  • TI-2025-35906 CoreDNS: DNS Cache Pinning via etcd Lease ID Confusion CVSS 3.1HIGH 7.1
See all 18 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences