CVE-2026-102484: Heap-based Buffer Overflow in ntpsec

Q: Which deployments are exposed to this issue?

Deployments running NTPsec ntpd before 1.2.6 are exposed if they use the JJY refclock driver and receive time replies from a Telephone JJY time source controlled by an attacker.

Q: What does an attacker need to do to trigger the flaw?

The attacker must control the Telephone JJY time source used by the affected ntpd instance and send more than six time replies. No privileges or user interaction are required according to the provided vector.

Q: What is the impact of successful exploitation?

Successful exploitation can corrupt ntpd memory or crash the ntpd process. The supplied severity vector also indicates potential high integrity and availability impact, with low confidentiality impact.

Q: How can I remediate the issue?

Upgrade NTPsec ntpd to version 1.2.6 or later. If an immediate upgrade is not possible, the provided information only identifies the JJY refclock path as affected; it does not specify a supported workaround.

Published Oct 21, 2026

Updated

Heap-based buffer overflow in the JJY refclock driver in NTPsec ntpd before 1.2.6 allows an attacker who controls the Telephone JJY time source to corrupt memory or crash ntpd via more than six time replies.

Affected Software

1 affected component

NTPsec ntpd<1.2.6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ntpsec/ntpd to a version that resolves this vulnerability.
Fixed in 1.2.6

Event History

Oct 21, 2026

CVE Published

via MITRE·03:03 PM

Data Sourced

via MITRE·03:03 PM

RemedyDescriptionSeverityWeakness

Frequently Asked Questions

Which deployments are exposed to this issue?

Deployments running NTPsec ntpd before 1.2.6 are exposed if they use the JJY refclock driver and receive time replies from a Telephone JJY time source controlled by an attacker.

What does an attacker need to do to trigger the flaw?

The attacker must control the Telephone JJY time source used by the affected ntpd instance and send more than six time replies. No privileges or user interaction are required according to the provided vector.

What is the impact of successful exploitation?

Successful exploitation can corrupt ntpd memory or crash the ntpd process. The supplied severity vector also indicates potential high integrity and availability impact, with low confidentiality impact.

How can I remediate the issue?

Upgrade NTPsec ntpd to version 1.2.6 or later. If an immediate upgrade is not possible, the provided information only identifies the JJY refclock path as affected; it does not specify a supported workaround.

CVE-2026-102484: Heap-based Buffer Overflow in ntpsec

Affected Software

Remediation

Event History

Frequently Asked Questions

Which deployments are exposed to this issue?

What does an attacker need to do to trigger the flaw?

What is the impact of successful exploitation?

How can I remediate the issue?

Company

Resources

Contact

Frequently Asked Questions

Which deployments are exposed to this issue?

What does an attacker need to do to trigger the flaw?

What is the impact of successful exploitation?

How can I remediate the issue?