How severe is CVE-2025-47950?

CVE-2025-47950 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-47950?

CVE-2025-47950 affects the following packages: github.com/coredns/coredns (Go). Ecosystems affected: Go.

How do I fix CVE-2025-47950?

Update github.com/coredns/coredns to 1.12.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-47950 is resolved across your whole dependency graph.

How do I detect CVE-2025-47950 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coredns/coredns. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2025-47950 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-47950?

O3 pinpoints whether CVE-2025-47950 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2025-47950 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-47950 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-47950?

CVE-2025-47950 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 62th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-47950?

CVE-2025-47950 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-47950 published, and has it been updated?

CVE-2025-47950 was published on June 6, 2025 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-47950: coredns Denial of Service (High 7.5)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk62th percentile+0.98%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐹github.com/coredns/coredns

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/coredns/coredns`	all versions	1.12.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coredns/coredns. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/coredns/coredns to 1.12.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-47950 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-47950 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-47950. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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 int

O3 Security · Impact-Aware SCA

Is CVE-2025-47950 in your dependencies?

O3 detects CVE-2025-47950 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2025-47950