CVE-2026-18321: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in ntpsec
Published Jul 31, 2026
·Updated
Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd
Affected Software
1 affected component
NTPsec=
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ntpsecto a version that resolves this vulnerability.Fixed in 1.2.5
Event History
Jul 31, 2026
CVE Published
via MITRE·06:04 PM
Data Sourced
via MITRE·06:04 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·07:17 PM
DescriptionSeverityWeakness
Frequently Asked Questions
1
What is the severity of CVE-2026-18321?
The severity of CVE-2026-18321 is rated as medium with a score of 4.7.
2
What does CVE-2026-18321 affect?
CVE-2026-18321 affects the NTPsec software, specifically the Zyfer refclock component.
3
How do I fix CVE-2026-18321?
To fix CVE-2026-18321, update NTPsec to the latest version where the buffer overflow vulnerability has been addressed.
4
What type of vulnerability is CVE-2026-18321?
CVE-2026-18321 is identified as a buffer overflow vulnerability.
5
Who can exploit CVE-2026-18321?
CVE-2026-18321 can be exploited by a local attacker to crash the ntpd service.