Resource exhaustion in Hickory-Dns
CVE-2026-123586
Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.
Vulnerability class: DoS (Denial of Service)
Published .
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: 0.003 (28.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
The 30-day trend appears once there are two daily scores.
Affected products
Weakness classification (CWE)
References
- github.com/hickory-dns/hickory-dns/security/advisories/GHSA-cx5j-p54p-q756 (vendor-advisory)
- www.vulncheck.com/advisories/hickory-dns-0.25.0-alpha.3-through-0.25.2-query-am… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-123586?
- CVE-2026-123586 is a high-severity vulnerability in Hickory-Dns, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-11-08.
- How severe is CVE-2026-123586?
- High severity. CVSS v3 base score is 7.5 out of 10.