CVE-2025-47950 (GCVE-0-2025-47950)

Vulnerability from cvelistv5 – Published: 2025-06-06 17:32 – Updated: 2025-06-06 21:27
VLAI
Title
CoreDNS Vulnerable to DoQ Memory Exhaustion via Stream Amplification
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-06-06 18:40 UTC
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
Impacted products
Vendor Product Version
coredns coredns Affected: < 1.12.2
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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