CVE-2026-18321
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in ntpsec
Description
Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd
INFO
Published Date :
July 31, 2026, 7:17 p.m.
Last Modified :
July 31, 2026, 7:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-18321
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | ceab7361-8a18-47b1-92ba-4d7d25f6715a | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update NTPsec to the latest version.
- Apply vendor-provided patches for NTPsec.
- Restart the ntpd service.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-18321.
| URL | Resource |
|---|---|
| https://gitlab.com/NTPsec/ntpsec/-/work_items/890 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-18321 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-18321
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-18321 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-18321 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 31, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'NTPsec', 'product': 'ntpsec', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.2.5', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] Added Description Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd Added CVSS V3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-120 Added Reference https://gitlab.com/NTPsec/ntpsec/-/work_items/890 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 31, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-18321', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-31T18:54:02.722476Z'}