CVE-2026-62994
Received Received - Intake

CoreDNS DNS Server Panic via Empty AXFR Response

Publication date: 2026-07-16

Last updated on: 2026-07-16

Assigner: GitHub, Inc.

Description
CoreDNS is a DNS server written in Go. From 1.9.4 until 1.14.5, a network DNS client allowed to request AXFR for a CoreDNS zone can trigger a panic when CoreDNS is configured with k8s_external headless-service zone transfers and Kubernetes contains a headless service endpoint with no declared ports; plugin/kubernetes/object/endpoint.go creates Port: -1, plugin/k8s_external/msg_to_dns.go skips that service, plugin/k8s_external/transfer.go sends an empty []dns.RR batch, and plugin/transfer/transfer.go indexes records[0] without checking the batch is non-empty. This issue is fixed in version 1.14.5.

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Meta Information

Published
2026-07-16
Last Modified
2026-07-16
Generated
2026-07-17
AI Q&A
2026-07-16
EPSS Evaluated
N/A
NVD
CVE-2026-62994
EUVD
EUVD-2026-45018

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
coredns coredns From 1.9.4 (inc) to 1.14.5 (exc)
coredns coredns 1.14.5
coredns coredns to 1.14.5 (inc)
coredns coredns 1.9.4
coredns coredns 1.14.4

Helpful Resources

Exploitability

CWE
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KEV
KEV Icon
CWE ID Description
CWE-755 The product does not handle or incorrectly handles an exceptional condition.
CWE-248 An exception is thrown from a function, but it is not caught.

Attack-Flow Graph

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Executive Summary

CoreDNS versions 1.9.4 to 1.14.4 have a flaw where a network DNS client can trigger a panic by requesting AXFR for a CoreDNS zone. This happens when CoreDNS is configured with k8s_external headless-service zone transfers and Kubernetes has a headless service endpoint with no ports. The system creates a Port: -1 value, skips the service, sends an empty DNS record batch, and then crashes when trying to access records[0] without checking if the batch is empty.

Detection Guidance

To detect this vulnerability, check CoreDNS version with 'coredns -version'. If running between 1.9.4 and 1.14.4, it is vulnerable. Monitor logs for panics or SERVFAIL responses during DNS queries. Check Kubernetes headless services for endpoints with no declared ports using 'kubectl get endpoints' and inspect service configurations.

Impact Analysis

This vulnerability can cause CoreDNS to panic, leading to service disruption. CoreDNS may recover and return SERVFAIL responses, but repeated attacks can degrade performance. If panic recovery is disabled, the CoreDNS process may crash entirely, causing DNS service outages.

Compliance Impact

This vulnerability primarily impacts system availability due to CoreDNS process crashes or repeated panics, which could disrupt DNS resolution in Kubernetes environments. While it does not directly expose or leak data, prolonged service disruption may interfere with logging, monitoring, or audit systems required by GDPR and HIPAA. However, the vulnerability itself does not directly violate these standards unless it leads to unauthorized access or data breaches.

Mitigation Strategies

Upgrade CoreDNS to version 1.14.5 or later immediately. If upgrading is not possible, disable the k8s_external plugin or configure Kubernetes headless services to always declare ports. Ensure panic recovery is enabled in CoreDNS configuration to minimize disruption.

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