CVE-2026-32934Public exploitNetwork attack vector

Unauthenticated service crash via unbounded QUIC streams

Published May 5, 2026 · Updated May 5, 2026

Denial of service in CoreDNS before 1.14.3 allows remote attackers to crash the DNS server through stalled DNS-over-QUIC streams. The DoQ path in core/dnsserver/server_quic.go spawns a waiter goroutine for every accepted stream after streamProcessPool fills, while io.ReadFull blocks on an incomplete two-byte length prefix without a stream deadline. Exploitation requires an exposed quic:// listener; one-byte streams can pin workers, grow memory without bounds, and trigger an OOM kill.

CVSS severity8.7
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in CoreDNS before 1.14.3 allows remote attackers to crash the DNS server through stalled DNS-over-QUIC streams. The DoQ path in core/dnsserver/server_quic.go spawns a waiter goroutine for every accepted stream after streamProcessPool fills, while io.ReadFull blocks on an incomplete two-byte length prefix without a stream deadline. Exploitation requires an exposed quic:// listener; one-byte streams can pin workers, grow memory without bounds, and trigger an OOM kill.

The record

CVE
CVE-2026-32934
Published
May 5, 2026
Updated
May 5, 2026
Vendor
CoreDNS
Product
CoreDNS
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 5, 2026CVE publishedPublication date reported by the CVE source.
  2. May 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.14.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CoreDNS · CoreDNSversion=< 1.14.3

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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