What is CVE-2026-18321?

CVE-2026-18321 is a medium-severity vulnerability in Ntpsec, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 4.7/10. Published 2026-07-31.

How severe is CVE-2026-18321?

Medium severity. CVSS v3 base score is 4.7 out of 10.

Buffer overflow in Ntpsec

CVE-2026-18321

Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Ntpsec — versions 0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

cve@gitlab.com

Frequently asked questions

What is CVE-2026-18321?: CVE-2026-18321 is a medium-severity vulnerability in Ntpsec, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 4.7/10. Published 2026-07-31.
How severe is CVE-2026-18321?: Medium severity. CVSS v3 base score is 4.7 out of 10.