Read the docs
TI-2026-21032 Aliases CVE-2026-26018GHSA-h75p-j8xm-m278

CoreDNS Loop Detection Denial of Service Vulnerability

Priority MEDIUM 41CWE-337Published · 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 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

CoreDNS is a DNS server that chains plugins. Prior to version 1.14.2, a denial of service vulnerability exists in CoreDNS's loop detection plugin that allows an attacker to crash the DNS server by sending specially crafted DNS queries. The vulnerability stems from the use of a predictable pseudo-random number generator (PRNG) for generating a secret query name, combined with a fatal error handler that terminates the entire process. This issue has been patched in version 1.14.2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01241 69th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial coredns (coredns): 1.14.2github.com/coredns/coredns (Go): 1.14.2Red Hat: 3 advisoriesRed Hat: 3 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
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 1.14.21.14.2Patch availableCNA
—github.com/coredns/coredns (Go)before 1.14.21.14.2Patch availableGHSA-h75p-j8xm-m278
  • coredns Vendorcoredns Affected before 1.14.2 Fixed in 1.14.2 Patch available CNA
  • github.com/coredns/coredns (Go) Vendor— Affected before 1.14.2 Fixed in 1.14.2 Patch available GHSA-h75p-j8xm-m278

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*before 1.14.2Vulnerablecoredns
  • cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:* Versions before 1.14.2 Vulnerable ·coredns

Remediation

  • Fix · CNA coredns (coredns) Fixed in 1.14.2
  • Fix · GHSA-h75p-j8xm-m278 github.com/coredns/coredns (Go) Fixed in 1.14.2 Advisory →

Red Hat 3 advisories

  • RHSA-2026:36873 Released 2026-07-08 · Red Hat rating Important
    Submariner v0.20 security fixes and container updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.13 registry.redhat.io/rhacm2/lighthouse-agent-rhel9, registry.redhat.io/rhacm2/lighthouse-coredns-rhel9, registry.redhat.io/rhacm2/nettest-rhel9 +5
  • RHSA-2026:25127 Released 2026-06-10 · Red Hat rating Important
    Submariner v0.21 security fixes and container updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.14 registry.redhat.io/rhacm2/lighthouse-agent-rhel9, registry.redhat.io/rhacm2/lighthouse-coredns-rhel9, registry.redhat.io/rhacm2/nettest-rhel9 +5
  • RHSA-2026:8151 Released 2026-04-14 · Red Hat rating Important
    Submariner v0.22 security fixes and container updates
    • Red Hat Advanced Cluster Management for Kubernetes 2.15 registry.redhat.io/rhacm2/lighthouse-agent-rhel9, registry.redhat.io/rhacm2/lighthouse-coredns-rhel9, registry.redhat.io/rhacm2/nettest-rhel9 +5

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 Advanced Cluster Management for Kubernetes 2.13Fixed RHSA-2026:36873
Red Hat Advanced Cluster Management for Kubernetes 2.14Fixed RHSA-2026:25127
Red Hat Advanced Cluster Management for Kubernetes 2.15Fixed RHSA-2026:8151
Not affected: 4 products
  • Red Hat Advanced Cluster Management for Kubernetes 2.13
  • Red Hat Advanced Cluster Management for Kubernetes 2.14
  • Red Hat Advanced Cluster Management for Kubernetes 2.15
  • Red Hat OpenShift Container Platform 4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26018
  2. 2026-10-03 Alias added: GHSA-h75p-j8xm-m278

References

Exploit 1

Advisory 1

Other 2

  • 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-2026-44486 NULL pointer dereference in coredns CVSS 3.1MEDIUM 5.3
See all 15 →

Sources

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