NTPsec up to 1.2.4 Zyfer refclock buffer overflow

Summaryinfo

A vulnerability labeled as critical has been found in NTPsec up to 1.2.4. Affected by this issue is some unknown functionality of the component Zyfer refclock. The manipulation results in buffer overflow. This vulnerability is reported as CVE-2026-18321. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in NTPsec up to 1.2.4. Affected is an unknown part of the component Zyfer refclock. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on availability. CVE summarizes:

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

The advisory is available at gitlab.com. This vulnerability is traded as CVE-2026-18321 since 07/29/2026. The exploitability is told to be easy. Local access is required to approach this attack. The technical details are unknown and an exploit is not available.

Upgrading to version 1.2.5 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-51593). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• NTPsec

Version

• 1.2.0
• 1.2.1
• 1.2.2
• 1.2.3
• 1.2.4

CPE 2.3info

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CPE 2.2info

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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