# CVE-2026-102486: NTPsec ntpd out-of-bounds read in NTS extension parsing

Source: https://junglewise.ai/threats/cve-2026-102486-out-of-bounds-read-in-nts-extension-field-parsing-in-ntpsec-ntpd  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-102486 · Severity: high · CVSS 7.5 · Published 2026-10-21

NTPsec ntpd is an open-source Network Time Protocol daemon used to synchronize system clocks across networks. A vulnerability in how it processes NTS (Network Time Security) extension fields allows a remote attacker to send a specially crafted network packet that crashes the daemon, disrupting time synchronization services on affected systems.

Technologies: [Ntpsec Ntpd](https://junglewise.ai/threats/technologies/ntpsec-ntpd). Vendors: [Ntpsec](https://junglewise.ai/threats/vendors/ntpsec).

## Quick answers

**Is CVE-2026-102486 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-102486 being exploited in the wild.

**How severe is CVE-2026-102486?** High severity, with a CVSS score of 7.5, published 21 October 2026.

**Which products and versions are affected?** Ntpsec Ntpd 1.1.4 through 1.2.5.

**Is there a fix for CVE-2026-102486?** Yes: fixed in NTPsec ntpd 1.2.6 or later (fix committed 2026-09-15). Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-102486 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-102486?** Check whether you run Ntpsec Ntpd at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in NTPsec ntpd 1.2.6 or later (fix committed 2026-09-15)

## Technical details

An out-of-bounds read vulnerability exists in the NTS extension field parser (nts_extens.c) where insufficient validation of the nonce length in Authenticator and Encrypted Extension Fields (AEEF) allows an attacker to read memory beyond allocated buffers. The vulnerability is triggered via a malformed NTS packet sent over the network and can cause denial of service through daemon crash. A fix validates that the nonce length matches the expected NONCE_LENGTH constant.

## Affected products

- NTPsec ntpd 1.1.4 through 1.2.5

## Timeline

- 2026-10-21: disclosed

## References

- [https://gitlab.com/NTPsec/ntpsec/-/commit/7cc079387](https://gitlab.com/NTPsec/ntpsec/-/commit/7cc079387)
- [https://gitlab.com/NTPsec/ntpsec/-/work_items/891](https://gitlab.com/NTPsec/ntpsec/-/work_items/891)

## Related threats

- [NTPsec ntpd out-of-bounds read in Motorola Oncore driver](https://junglewise.ai/threats/cve-2026-102485-out-of-bounds-read-in-the-motorola-oncore-refclock-driver-in)
- [NTPsec ntpd heap buffer overflow in JJY refclock driver](https://junglewise.ai/threats/cve-2026-102484-heap-based-buffer-overflow-in-the-jjy-refclock-driver-in-ntpsec)
- [NTPsec ntpd denial of service in NTS Cookie handling](https://junglewise.ai/threats/cve-2026-102483-reachable-exit-in-ntpsec-ntpd-1-1-4-through-1-2-5-allows-a)