What is CVE-2026-123597?

CVE-2026-123597 is a low-severity vulnerability in Hickory-Dns, classified under Insufficient Session Expiration. CVSS score: 3.7/10. Published 2026-11-08.

How severe is CVE-2026-123597?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in Hickory-Dns

CVE-2026-123597

Hickory DNS hickory-proto 0.25.0-alpha.1 through 0.26.0-alpha.1 and hickory-net before 0.26.2 contain a logic bug in DnssecDnsHandle's DS-fetch path that caches transient DS lookup errors as Bogus DNSSEC validation verdicts. An attacker who induces a SERVFAIL, REFUSED, or timeout response to a child-zone DS sub-query causes the validator to return SERVFAIL for all names under that zone until the cache entry's TTL expires.

Published 2026-11-08.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.002 (12.4th percentile), scored 2026-11-09.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.4% 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

Hickory-Dns

Weakness classification (CWE)

CWE-613 — Insufficient Session Expiration

References

github.com/hickory-dns/hickory-dns/security/advisories/GHSA-xv7c-h5g9-x25x (vendor-advisory)
www.vulncheck.com/advisories/hickory-dns-dnssec-validation-cache-poisoning-via-… (third-party-advisory)

Frequently asked questions

What is CVE-2026-123597?: CVE-2026-123597 is a low-severity vulnerability in Hickory-Dns, classified under Insufficient Session Expiration. CVSS score: 3.7/10. Published 2026-11-08.
How severe is CVE-2026-123597?: Low severity. CVSS v3 base score is 3.7 out of 10.