What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-16 · updated 2026-07-22
• Weakness: CWE-476

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.

Affected products

• coredns: before 1.14.4 — fixed in 1.14.4

How to fix

Upgrade to a fixed version: coredns 1.14.4. Check the vendor advisory for mitigations.

References

• https://github.com/coredns/coredns/commit/60a439dd4febfcd78e3779e952fe3fbf3c16bb1f
• https://github.com/coredns/coredns/pull/8154
• https://github.com/coredns/coredns/releases/tag/v1.14.4
• https://github.com/coredns/coredns/security/advisories/GHSA-9rvv-m5g5-wc8r

Get alerted when CVE-2026-62309 or the next vulnerability affects your stack