What is CVE-2026-123571?

CVE-2026-123571 is a high-severity vulnerability in Hickory-Dns, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-11-08.

How severe is CVE-2026-123571?

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

Integer overflow in Hickory-Dns

CVE-2026-123571

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

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-191 — Integer Underflow

References

GitHub Security Advisory (GHSA-x962-5xwx-fr8x) (vendor-advisory)
VulnCheck Advisory: Hickory DNS from 0.26.0 before 0.26.2 Panic via TSIG RDATA Decoding (third-party-advisory)

Frequently asked questions

What is CVE-2026-123571?: CVE-2026-123571 is a high-severity vulnerability in Hickory-Dns, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-11-08.
How severe is CVE-2026-123571?: High severity. CVSS v3 base score is 7.5 out of 10.