How severe is CVE-2026-32934?

CVE-2026-32934 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-2026-32934 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-32934?

CVE-2026-32934 affects Coredns.io Coredns. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-32934?

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.

Does CVE-2026-32934 have an EU (EUVD) identifier?

Yes. CVE-2026-32934 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27440.

When was CVE-2026-32934 published?

CVE-2026-32934 was published on 2026-05-05 and last updated on 2026-07-25.

CVE-2026-32934

CVE-2026-32934 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27440
Weakness: CWE-770
Affected product: Coredns.io Coredns
Published: 2026-05-05
Last modified: 2026-07-25

Description

CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-QUIC (DoQ) server can be driven into unbounded goroutine and memory growth by a remote client that opens many QUIC streams and sends only 1 byte per stream. When the worker pool is full, CoreDNS still spawns a goroutine per accepted stream to wait for a worker token. Additionally, active workers block indefinitely in io.ReadFull() with no per-stream read deadline, allowing an attacker to pin all workers by sending a single byte so the read blocks waiting for the second byte of the DoQ length prefix. This enables an unauthenticated remote attacker to cause memory exhaustion and OOM-kill. This issue has been fixed in version 1.14.3. No known workarounds exist.

Frequently asked questions

What is CVE-2026-32934?: CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-QUIC (DoQ) server can be driven into unbounded goroutine and memory growth by a remote client that opens many QUIC streams and sends only 1 byte per stream. When the worker pool is full, CoreDNS still spawns a goroutine per accepted stream to wait for a worker token. Additionally, active workers block indefinitely in io.ReadFull() with no per-stream read deadline, allowing an attacker to pin all workers by sending a single byte so the read blocks waiting for the second byte of the DoQ length prefix. This enables an unauthenticated remote attacker to cause memory exhaustion and OOM-kill. This issue has been fixed in version 1.14.3. No known workarounds exist.
How severe is CVE-2026-32934?: CVE-2026-32934 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-2026-32934 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-32934?: CVE-2026-32934 affects Coredns.io Coredns. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-32934?: 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.
Does CVE-2026-32934 have an EU (EUVD) identifier?: Yes. CVE-2026-32934 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27440.
When was CVE-2026-32934 published?: CVE-2026-32934 was published on 2026-05-05 and last updated on 2026-07-25.

References

Affected products (1)

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

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