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CVE-2026-62994 low CVSS 3.7

Vulnerability in github.com/coredns/coredns (CVE-2026-62994)

Summary

Vulnerability in github.com/coredns/coredns (CVE-2026-62994). Risk of unauthorized operations or information disclosure. Exploitable via k8s_external. Mitigation: upgrade to 1.14.5 or later.

Original description

The description as published by the source.

Summary

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. The built-in k8s_external transferer can emit an empty []dns.RR batch, and the shared transfer plugin indexes records[0] without checking that the batch is non-empty. In normal CoreDNS mode the panic is recovered and returned as SERVFAIL, but repeated triggering can disrupt requests and amplify panic logging; if the debug plugin disables recovery, the same path can crash the CoreDNS process.

Details

plugin/transfer/transfer.go assumes that every Transferer emits only non-empty []dns.RR batches. During AXFR/IXFR response generation it indexes records[0] without checking the slice length:

  • plugin/transfer/transfer.go:129-131
for records := range pchan {
    if x, ok := records[0].(*dns.SOA); ok && soa == nil {
        soa = x
    }

The built-in k8s_external transferer violates that contract for headless services whose endpoints have no declared ports. plugin/k8s_external/transfer.go sends the SRV result slice unconditionally:

  • plugin/k8s_external/transfer.go:104-106
recs, _ := e.srv(ctx, svcs, s)
ch <- recs

plugin/k8s_external/msg_to_dns.go intentionally skips services whose port is -1:

  • plugin/k8s_external/msg_to_dns.go:107-112
for _, s := range services…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-62994 has been found in github.com/coredns/coredns.
Attackers can target a specific entry point like k8s_external over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.7/10.
What to do: upgrade github.com/coredns/coredns to 1.14.5 or later.
If unsure, ask your IT team or search "github.com/coredns/coredns CVE-2026-62994" on the vendor's site.

CVE-2026-62994 (github.com/coredns/coredns) — CWE-248 / CVSS v3 3.7
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: k8s_external / transfer / SERVFAIL / debug
Patched: 1.14.5 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-248) exists in github.com/coredns/coredns. Attackers reach the vulnerable code path via k8s_external without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/coredns/coredns. Attack surface: k8s_external / transfer / SERVFAIL / debug.

🔥 Severity

Severity: Low (CVSS 3.7/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.14.5.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/coredns/coredns' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'github.com/coredns/coredns' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/coredns/coredns を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade github.com/coredns/coredns to 1.14.5

    ステージング環境で 1.14.5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go github.com/coredns/coredns
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.14.5"}]}]

References

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