CVE-2026-62309

highCVSS 7.5covered by 2 sourcesfirst seen 2026-07-14

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.

CSIRTS triage

What: The proxyproto plugin panics when processing a PPv2 datagram with a non-UDP transport, leading to a denial of service.
Who is affected: Deployments of CoreDNS using the proxyproto plugin.
Urgency: Remediation is urgent due to the high severity and potential for denial of service.
Action: Update to the latest version of CoreDNS that addresses this issue.

AI-assisted analysis generated from the source advisory — verify against the original.

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Exploitation outlook

Low exploitation risk0.38% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all EPSS-scored CVEs.

Advisory coverage (2)

highCVE-2026-62309: CoreDNS is a DNS server written in Go. Prior to 1.14.4, a single 28-byte UDP datagram can cras…nvd · 2026-07-16
highCVE-2026-62309: CoreDNS: proxyproto plugin panics on PPv2 datagram with non-UDP transport — single 28-byte pac…msrc · 2026-07-14

External references

NVD record for CVE-2026-62309

CVE.org record

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