CVE-2025-47950

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.
CVSS

No CVSS.

Configurations

Configuration 1 (hide)

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

History

15 Aug 2025, 16:24

Type Values Removed Values Added
References () https://github.com/quic-go/quic-go - () https://github.com/quic-go/quic-go - Not Applicable
References () https://www.usenix.org/conference/usenixsecurity23/presentation/botella - () https://www.usenix.org/conference/usenixsecurity23/presentation/botella - Broken Link
References () https://github.com/coredns/coredns/security/advisories/GHSA-cvx7-x8pj-x2gw - () https://github.com/coredns/coredns/security/advisories/GHSA-cvx7-x8pj-x2gw - Vendor Advisory
References () https://github.com/coredns/coredns/commit/efaed02c6a480ec147b1f799aab7cf815b17dfe1 - () https://github.com/coredns/coredns/commit/efaed02c6a480ec147b1f799aab7cf815b17dfe1 - Patch
References () https://datatracker.ietf.org/doc/html/rfc9250 - () https://datatracker.ietf.org/doc/html/rfc9250 - Technical Description
CPE cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*
First Time Coredns.io
Coredns.io coredns

06 Jun 2025, 22:15

Type Values Removed Values Added
Summary CoreDNS is a DNS server that chains plugins. In versions prior to 1.21.2, 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 1.21.2 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. 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.
CWE CWE-770

06 Jun 2025, 18:15

Type Values Removed Values Added
New CVE

Information

Published : 2025-06-06 18:15

Updated : 2025-08-15 16:24


NVD link : CVE-2025-47950

Mitre link : CVE-2025-47950


JSON object : View

Products Affected

coredns.io

  • coredns
CWE

No CWE.