---
id: CVE-2026-62309
title: CoreDNS is a DNS server written in Go
summary: >-
  CoreDNS is a DNS server written in Go. Prior to 1.14.4, a single 28-byte UDP
  datagram can crash the CoreDNS process when the proxyproto plugin is enabled
  because plugin/pkg/proxyproto/proxyproto.go PacketConn.ReadFrom handles a
  PROXY v2 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
published: '2026-07-16'
updated: '2026-07-18'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-62309'
references:
  - url: >-
      https://github.com/coredns/coredns/commit/60a439dd4febfcd78e3779e952fe3fbf3c16bb1f
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/pull/8154'
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/releases/tag/v1.14.4'
    label: security-advisories@github.com
  - url: 'https://github.com/coredns/coredns/security/advisories/GHSA-9rvv-m5g5-wc8r'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-62309.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-62309'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2501535'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-62309'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-62309'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63016'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00662
epssPercentile: 0.49558
ingestedAt: '2026-07-18T20:24:54.544Z'
vendor: Red Hat
product: Red Hat Advanced Cluster Management for Kubernetes 2.17
affected:
  - connectivity_link 1
  - openshift_container_platform 4
  - advanced_cluster_management_for_kubernetes 2.17
patched:
  - advanced_cluster_management_for_kubernetes 2.17
---

## Overview

CoreDNS is a DNS server written in Go. Prior to 1.14.4, a single 28-byte UDP datagram can crash the CoreDNS process when the proxyproto plugin is enabled because plugin/pkg/proxyproto/proxyproto.go PacketConn.ReadFrom handles a PROXY v2 header with non-UDP transport such as family byte 0x11, reassigns addr from a nil readFrom result after parseProxyProtocol errors, and calls addr.String() in the warning log before ServeDNS recovery applies. This issue is fixed in version 1.14.4.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:63016** · Red Hat · fixed in: Red Hat Advanced Cluster Management for Kubernetes 2.17 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63016)
- **Red Hat VEX** · Important · affected: Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Connectivity Link 1, Red Hat OpenShift Container Platform 4 · updated 2026-09-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-62309.json)