CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-770.
Summary
CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-QUIC (DoQ) server can be driven into unbounded goroutine and memory growth by a remote client that opens many QUIC streams and sends only 1 byte per stream. When the worker pool is full, CoreDNS still spawns a goroutine per accepted stream to wait for a worker token. Additionally, active workers block indefinitely in io.ReadFull() with no per-stream read deadline, allowing an attacker to pin all workers by sending a single byte so the read blocks waiting for the second byte of the DoQ length prefix. This enables an unauthenticated remote attacker to cause memory exhaustion and OOM-kill. This issue has been fixed in version 1.14.3. No known workarounds exist.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| coredns | coredns | before 1.14.3 | 1.14.3 | Patch available | CNA |
| — | github.com/coredns/coredns (Go) | before 1.14.3 | 1.14.3 | Patch available | GHSA-2wpx-qpw2-g5h5 |
- coredns Vendorcoredns Affected before 1.14.3 Fixed in 1.14.3 Patch available CNA
- github.com/coredns/coredns (Go) Vendor— Affected before 1.14.3 Fixed in 1.14.3 Patch available GHSA-2wpx-qpw2-g5h5
Remediation
- Fix · CNA coredns (coredns) Fixed in 1.14.3
- Fix · GHSA-2wpx-qpw2-g5h5 github.com/coredns/coredns (Go) Fixed in 1.14.3 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-32934
- 2026-10-03 Alias added: GHSA-2wpx-qpw2-g5h5
References
More Coredns vulnerabilities
- TI-2026-25615 CoreDNS TSIG authentication bypass on encrypted DNS transports CVSS 4.0HIGH 8.7
- TI-2026-25384 CoreDNS DoH GET path missing size validation causes CPU and memory amplification CVSS 4.0HIGH 8.7
- TI-2026-27682 CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports CVSS 4.0HIGH 8.2
- TI-2026-25885 CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison CVSS 4.0HIGH 8.2
- TI-2026-44486 NULL pointer dereference in coredns CVSS 3.1MEDIUM 5.3
- TI-2026-44995 CoreDNS `k8s_external` headless AXFR can emit an empty transfer batch that panics the `transfer` plugin CVSS 3.1LOW 3.7
Sources
- CVE-2026-32934 · CVE Program
- CVE-2026-32934 · NVD
- FIRST EPSS
- GHSA-2wpx-qpw2-g5h5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-32934 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences