Resource exhaustion in Coredns
CVE-2026-32934
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (49.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.002
Affected products
- Coredns — versions < 1.14.3
- Coredns.io Coredns
Weakness classification (CWE)
References
- github.com/coredns/coredns/security/advisories/GHSA-2wpx-qpw2-g5h5 (Exploit, Vendor Advisory)
- github.com/coredns/coredns/releases/tag/v1.14.3 (Release Notes)
Frequently asked questions
- What is CVE-2026-32934?
- CVE-2026-32934 is a high-severity vulnerability in Coredns, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-05.
- How severe is CVE-2026-32934?
- High severity. CVSS v3 base score is 7.5 out of 10.