CVE-2025-47950: coredns · Unthrottled Resource Allocation
Affects corednsSource CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade to 1.12.2 soon.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 1.1% chance of exploitation in 30 days – higher than 67% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.12.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade github.com/coredns/coredns to 1.12.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Gogithub.com/coredns/corednspkg:golang/github.com/coredns/corednsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To effectively mitigate this vulnerability, European organizations should prioritize upgrading CoreDNS to version 1.12.2 or later, which includes the necessary patches to limit concurrent QUIC streams and implement a bounded worker pool. For environments where immediate upgrade is not feasible, disabling the DNS-over-QUIC feature by removing or commenting out the 'quic://' block in the Corefile is a practical interim measure. Organizations should also enforce strict container runtime resource limits to detect and contain excessive memory usage, preventing OOM crashes from affecting the host or other containers. Implementing monitoring and alerting on QUIC connection patterns can provide early detection of anomalous activity indicative of exploitation attempts. Network-level controls, such as rate limiting and firewall rules, can be configured to restrict the number of incoming QUIC connections or streams from untrusted sources. Additionally, organizations should review and update incident response plans to include scenarios involving DNS service disruption. Regular security audits and penetration testing focusing on DNS infrastructure resilience can help identify residual risks. Finally, maintaining up-to-date threat intelligence feeds and vendor advisories will ensure timely awareness of any emerging exploits related to this vulnerability.
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.
References
- github.com/coredns/coredns/security/advisories/GHSA-cvx7-x8pj-x2gw (opens in a new tab)
- github.com/coredns/coredns/commit/efaed02c6a480ec147b1f799aab7cf815b17dfe1 (opens in a new tab)
- datatracker.ietf.org/doc/html/rfc9250 (opens in a new tab)
- github.com/quic-go/quic-go (opens in a new tab)
- usenix.org/conference/usenixsecurity23/presentation/botella (opens in a new tab)