What is CVE-2026-123604?

CVE-2026-123604 is a high-severity vulnerability in Hickory-Dns, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2026-11-08.

How severe is CVE-2026-123604?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Hickory-Dns

CVE-2026-123604

Hickory DNS hickory-resolver 0.26.0-beta.1 before 0.26.2 contains an unbounded retry loop in NameServerPool::try_send, which re-queues truncated (TC) responses without checking the answering transport or counting iterations. A malicious authoritative server returning TC=1 on every transport keeps the resolver spinning on a persistent TCP connection until the 5-second request deadline expires, causing resource exhaustion.

Published 2026-11-08.

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

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Hickory-Dns

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

GitHub Security Advisory (GHSA-6w6g-hm98-mhgm) (vendor-advisory)
VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop (third-party-advisory)

Frequently asked questions

What is CVE-2026-123604?: CVE-2026-123604 is a high-severity vulnerability in Hickory-Dns, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2026-11-08.
How severe is CVE-2026-123604?: High severity. CVSS v3 base score is 7.5 out of 10.