Security readout for executives and security teams
Plain-English summary
CoreDNS versions before 1.14.4 can crash when the proxyproto plugin receives a malformed PROXY protocol v2 datagram over UDP. For organizations relying on CoreDNS for service discovery or public DNS, this is primarily an availability risk: a remote unauthenticated sender could interrupt DNS resolution.
Executive priority
Treat this as urgent for exposed or business-critical DNS infrastructure. It is not a data theft issue, but DNS process crashes can disrupt applications, Kubernetes service discovery, and customer-facing availability.
Technical view
The issue is a nil pointer dereference in plugin/pkg/proxyproto/proxyproto.go. PacketConn.ReadFrom mishandles a PROXY v2 header using a non-UDP transport, then logs addr.String() after addr may be nil. The crash happens before normal ServeDNS recovery applies. CoreDNS 1.14.4 fixes the flaw.
Likely exposure
Exposure is limited to CoreDNS deployments before 1.14.4 with the proxyproto plugin enabled and reachable over UDP. Kubernetes clusters, service meshes, or edge DNS deployments should verify whether CoreDNS is vendor-packaged and whether proxy protocol support is configured.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. The CVSS 7.5 rating reflects network access, low complexity, no privileges, no user interaction, and high availability impact.
Researcher notes
Evidence supports CoreDNS before 1.14.4 with proxyproto enabled as affected. The public bundle names the vulnerable code path and fixing release, but does not provide broader downstream vendor package status or exploitation telemetry.
Mitigation direction
- Upgrade CoreDNS to 1.14.4 or later.
- Disable proxyproto where it is not required until patched.
- Restrict UDP access to CoreDNS to trusted infrastructure where feasible.
- Review the CoreDNS advisory and release notes before rollout.
- Monitor CoreDNS restarts and DNS availability during remediation.
Validation and detection
- Identify all CoreDNS instances and record their versions.
- Inspect CoreDNS configuration for proxyproto plugin usage.
- Confirm upgraded binaries report version 1.14.4 or later.
- Verify DNS health checks remain stable after upgrade.
- Review logs for panic crashes or unexpected restarts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-476: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-62309 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6GitHub_MVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/coredns/coredns/security/advisories/GHSA-9rvv-m5g5-wc8rCVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/coredns/coredns/pull/8154CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/coredns/coredns/commit/60a439dd4febfcd78e3779e952fe3fbf3c16bb1fCVE reference, GitHub_M · x_refsource_MISC
- https://github.com/coredns/coredns/releases/tag/v1.14.4CVE reference, GitHub_M · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.