# NTPsec vulnerabilities

Source: https://junglewise.ai/threats/technologies/ntpsec  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 11 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/technologies/ntpsec.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 3 vulnerabilities in NTPsec: 0 in the last 7 days and 1 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-121506, was published on 3 November 2026. 1 vulnerability in the last four weeks, up from none in the four before.

## Counts

- Last 7 days: 0
- Last 30 days: 1
- Last 90 days: 1
- All time: 3 (0 critical, 0 exploited in the wild)

## About NTPsec

Secure, hardened implementation of the Network Time Protocol for time synchronization.

## Latest NTPsec vulnerabilities

- [CVE-2026-121506: NTPsec out-of-bounds read/write in NTS client extension parsing](https://junglewise.ai/threats/cve-2026-121506-an-out-of-bounds-read-and-write-in-nts-client-extension-field) (high, CVSS 7.4, published 3 Nov 2026)
- [CVE-2026-18321: NTPsec buffer overflow in Zyfer refclock](https://junglewise.ai/threats/cve-2026-18321-ntpsec-buffer-overflow-in-zyfer-refclock) (medium, CVSS 4.7, published 31 Jul 2026)
- [CVE-2016-1551: NTP and NTPsec reference clock impersonation vulnerability](https://junglewise.ai/threats/cve-2016-1551-ntp-and-ntpsec-reference-clock-impersonation-vulnerability) (low, CVSS 3.7, published 27 Jan 2017)

## Most severe NTPsec vulnerabilities

- [CVE-2026-121506: NTPsec out-of-bounds read/write in NTS client extension parsing](https://junglewise.ai/threats/cve-2026-121506-an-out-of-bounds-read-and-write-in-nts-client-extension-field) (high, CVSS 7.4, published 3 Nov 2026)
- [CVE-2026-18321: NTPsec buffer overflow in Zyfer refclock](https://junglewise.ai/threats/cve-2026-18321-ntpsec-buffer-overflow-in-zyfer-refclock) (medium, CVSS 4.7, published 31 Jul 2026)
- [CVE-2016-1551: NTP and NTPsec reference clock impersonation vulnerability](https://junglewise.ai/threats/cve-2016-1551-ntp-and-ntpsec-reference-clock-impersonation-vulnerability) (low, CVSS 3.7, published 27 Jan 2017)

## Vulnerabilities per week

1 vulnerability in the last four weeks, up from none in the four before.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 1 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Other Ntpsec technologies

- [Ntpsec Ntpd](https://junglewise.ai/threats/technologies/ntpsec-ntpd): 4 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "NTPsec vulnerabilities", https://junglewise.ai/threats/technologies/ntpsec, 11 November 2026.