How severe is CVE-2026-62309?

CVE-2026-62309 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-62309 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-62309?

CVE-2026-62309 affects Coredns.io Coredns. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-62309?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-62309 published?

CVE-2026-62309 was published on 2026-07-16 and last updated on 2026-07-22.

CVE-2026-62309

CVE-2026-62309 is a high-severity vulnerability in Coredns.io Coredns with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Coredns.io Coredns
Published: 2026-07-16
Last modified: 2026-07-22

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.

Frequently asked questions

What is CVE-2026-62309?: 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.
How severe is CVE-2026-62309?: CVE-2026-62309 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-62309 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-62309?: CVE-2026-62309 affects Coredns.io Coredns. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-62309?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-62309 published?: CVE-2026-62309 was published on 2026-07-16 and last updated on 2026-07-22.

References

Affected products (1)

cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*

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