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CVE-2026-62309— CoreDNS: proxyproto plugin panics on PPv2 datagram with non-UDP transport — single 28-byte packet remote DoS

Quick assessment

Affected
coredns coredns
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

CoreDNS是CoreDNS团队开源的一个 DNS 服务器。 CoreDNS 1.14.4之前版本存在异常处理不当漏洞，该漏洞源于 proxyproto 插件对 PROXY v2 头部非 UDP 传输的处理不当，导致解析错误后从空结果重新分配地址，并在 ServeDNS 恢复前调用 addr.String() 在警告日志中，从而可能使单个 28 字节 UDP 数据包崩溃 CoreDNS 进程，造成拒绝服务。

CVSS 7.5 · High EPSS 0.66% · P50

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth

Affected Version Matrix 1

VendorProduct Version RangeStatus
coredns coredns < 1.14.4 affected
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I. Basic Information for CVE-2026-62309

Vulnerability Information
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Vulnerability Title
CoreDNS: proxyproto plugin panics on PPv2 datagram with non-UDP transport — single 28-byte packet remote DoS
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
空指针解引用
Source: CVE Program / CVE List V5
Vulnerability Title
CoreDNS 异常处理不当漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
CoreDNS是CoreDNS团队开源的一个 DNS 服务器。 CoreDNS 1.14.4之前版本存在异常处理不当漏洞，该漏洞源于 proxyproto 插件对 PROXY v2 头部非 UDP 传输的处理不当，导致解析错误后从空结果重新分配地址，并在 ServeDNS 恢复前调用 addr.String() 在警告日志中，从而可能使单个 28 字节 UDP 数据包崩溃 CoreDNS 进程，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
coredns coredns < 1.14.4 -

II. Public POCs for CVE-2026-62309

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 5840 chars
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III. Intelligence Information for CVE-2026-62309

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Patches & Fixes for CVE-2026-62309 (2)

Vendor Advisories for CVE-2026-62309 (1)

Same Patch Batch · coredns · 2026-07-16 · 3 CVEs total

CVE-2026-62299 5.3 MEDIUM CoreDNS: rewrite-plugin EDNS0 response-revert nil-pointer panic (remote DoS) when a downst
CVE-2026-62994 3.7 LOW CoreDNS `k8s_external` headless AXFR can emit an empty transfer batch that panics the `tra

IV. Related Vulnerabilities

Same product: coredns
Same vendor: coredns
Same weakness: CWE-476

V. Comments for CVE-2026-62309

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