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Fencer Vulns
high 7.5

CVE-2025-47950 json

CoreDNS Vulnerable to DoQ Memory Exhaustion via Stream Amplification

published 2025-06-06 17 mo ago modified 2026-09-10 1 mo ago also EUVD-2025-17359 , GHSA-cvx7-x8pj-x2gw , GO-2025-3743

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

CoreDNS is a DNS server that chains plugins. In versions prior to 1.12.2, a Denial of Service (DoS) vulnerability exists in the CoreDNS DNS-over-QUIC (DoQ) server implementation. The server previously created a new goroutine for every incoming QUIC stream without imposing any limits on the number of concurrent streams or goroutines. A remote, unauthenticated attacker could open a large number of streams, leading to uncontrolled memory consumption and eventually causing an Out Of Memory (OOM) crash — especially in containerized or memory-constrained environments. The patch in version 1.12.2 introduces two key mitigation mechanisms: `max_streams`, which caps the number of concurrent QUIC streams per connection with a default value of `256`; and `worker_pool_size`, which Introduces a server-wide, bounded worker pool to process incoming streams with a default value of `1024`. This eliminates the 1:1 stream-to-goroutine model and ensures that CoreDNS remains resilient under high concurrency. Some workarounds are available for those who are unable to upgrade. Disable QUIC support by removing or commenting out the `quic://` block in the Corefile, use container runtime resource limits to detect and isolate excessive memory usage, and/or monitor QUIC connection patterns and alert on anomalies.

Patch / fix

  • go github.com/coredns/coredns 1.12.2
  • coredns.io coredns 1.12.2
  • govulncheck-vulndb openSUSE Tumbleweed 0.0.20250612T141001-1.1

opensuse advisories openSUSE-SU-2025:15225-1

  • coredns Azure Linux 3.0 1.11.4-7
  • coredns CBL-Mariner 2.0 1.11.1-19

azure linux advisories AZL-63678AZL-63695

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-47950 updated cvss 5.3

coredns: CoreDNS Vulnerable to DoQ Memory Exhaustion via Stream Amplification

  • Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2 v0.20.2-1759168533, rhacm2/lighthouse-agent-rhel9 1782924920, rhacm2/lighthouse-coredns-rhel9 1782924937
    fixed: vendor fix “Users unable to upgrade should manually disable the QUIC protocol support.” RHSA-2026:36873
  • Red Hat Advanced Cluster Management for Kubernetes 2.14 rhacm2 v0.21-1762794425, rhacm2 v0.21-1762794442
    fixed: vendor fix “Users unable to upgrade should manually disable the QUIC protocol support.” RHSA-2025:21892
  • Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2 v0.20.2-1759147029, rhacm2 v0.20.2-1759147035, rhacm2 v0.20.2-1759147041, rhacm2 v0.20.2-1759153685, rhacm2 v0.20.2-1759168503, rhacm2 v0.20.2-1759202884, +9 more Red Hat Advanced Cluster Management for Kubernetes 2.14 rhacm2 v0.21-1762272934, rhacm2 v0.21-1762820727, rhacm2 v0.21-1763479084, rhacm2 v0.21-1763479094, rhacm2 v0.21-1763479111, rhacm2 v0.21-1763479473, +1 more Red Hat OpenShift Container Platform 4 openshift4/ose-coredns, openshift4/ose-coredns-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/coredns/coredns
<1.12.2
1.12.2

Affected products

  • coredns coredns

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.