CVE-2025-47950 CoreDNS Vulnerable to DoQ Memory Exhaustion via Stream Amplification

What is CVE-2025-47950?

CVE-2025-47950 is a high-severity vulnerability in coredns, published on 6 Jun 2025.

Official description

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.

Weakness: CWE-770

Which versions are affected by CVE-2025-47950?

3 open source packages ship an affected version, including github.com/coredns/coredns. It affects 1 product.

Products include Coredns.io Coredns.

How do I fix CVE-2025-47950?

Upgrade github.com/coredns/coredns to 1.12.2 or later.

Is CVE-2025-47950 being exploited?

There is no known exploitation of CVE-2025-47950 in the wild and no public exploit code.

Other vulnerabilities in coredns

• CVE-2026-32934 CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service High 8.7
• CVE-2026-32936 CoreDNS DoH GET path missing size validation causes CPU and memory amplification High 8.7
• CVE-2026-33190 CoreDNS TSIG authentication bypass on encrypted DNS transports High 8.7
• CVE-2026-33489 CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison High 8.2
• CVE-2026-35579 CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports High 8.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-63678, AZL-63695, CLEANSTART-2026-QH90790, CLEANSTART-2026-WO45616, ECHO-fe0d-9184-e720, GHSA-cvx7-x8pj-x2gw and 7 more.