CVE-2026-18321

MEDIUMPre-NVD 4.74.7—
EchelonGraph scoreHIGH confidence

Score 4.7 from GitHub Security Advisory published 2026-07-31. a secondary CVSS source baseline 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
4.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.7Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
4.7
EG Score
4.7(high)
EG Risk
26(Track)
EG Risk 26/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity47% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
0%
KEV
Not listed

Published

July 31, 2026

Last Modified

July 31, 2026

Advisory Details (1)

Auto-updated Jul 31, 2026
No patch confirmed yet.
generic

NTPsec / ntpsec · GitLab

https://gitlab.com/NTPsec/ntpsec/-/work_items/890

Vendor Advisories for CVE-2026-18321(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ntpsec1.2.0+dfsg1-4 ... 1.2.4+dfsg-1 (22 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ntpsec1.2.2+dfsg1-1 ... 1.2.4+dfsg-1 (14 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ntpsec1.2.3+dfsg1-8, 1.2.4+dfsg-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ntpsec1.2.3+dfsg1-8, 1.2.4+dfsg-1——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 41× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 16:50 UTCGHSA enrichment
  2. 2026-08-19 19:06 UTCGHSA enrichment
  3. 2026-08-18 20:21 UTCGHSA enrichment
  4. 2026-08-17 22:30 UTCEG score recompute
  5. 2026-08-17 22:30 UTCGHSA enrichment
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-17 00:52 UTCEG score recompute
  8. 2026-08-17 00:52 UTCGHSA enrichment
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 03:14 UTCGHSA enrichment
  11. 2026-08-15 05:36 UTCGHSA enrichment
  12. 2026-08-14 07:57 UTCGHSA enrichment
  13. 2026-08-13 10:19 UTCGHSA enrichment
  14. 2026-08-12 12:41 UTCGHSA enrichment
  15. 2026-08-11 15:02 UTCGHSA enrichment
  16. 2026-08-10 17:24 UTCGHSA enrichment
  17. 2026-08-09 19:46 UTCGHSA enrichment
  18. 2026-08-08 22:08 UTCEG score recompute
  19. 2026-08-08 22:08 UTCGHSA enrichment
  20. 2026-08-08 16:37 UTCEPSS rescore
  21. 2026-08-08 00:29 UTCGHSA enrichment
  22. 2026-08-07 02:51 UTCEG score recompute
  23. 2026-08-07 02:51 UTCGHSA enrichment
  24. 2026-08-06 13:46 UTCEPSS rescore
  25. 2026-08-06 05:13 UTCEG score recompute
Show 16 more
  1. 2026-08-06 05:13 UTCGHSA enrichment
  2. 2026-08-05 19:17 UTCEPSS rescore
  3. 2026-08-05 07:35 UTCEG score recompute
  4. 2026-08-05 07:35 UTCGHSA enrichment
  5. 2026-08-04 15:10 UTCEPSS rescore
  6. 2026-08-04 10:38 UTCEPSS rescore
  7. 2026-08-04 09:57 UTCGHSA enrichment
  8. 2026-08-03 12:19 UTCGHSA enrichment
  9. 2026-08-02 14:40 UTCEG score recompute
  10. 2026-08-02 14:40 UTCGHSA enrichment
  11. 2026-08-02 02:26 UTCEPSS rescore
  12. 2026-08-01 17:02 UTCEG score recompute
  13. 2026-08-01 17:02 UTCGHSA enrichment
  14. 2026-07-31 19:23 UTCEG score recompute
  15. 2026-07-31 18:43 UTCEG score recompute
  16. 2026-07-31 18:43 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-18321?
CVE-2026-18321 is a medium vulnerability published on July 31, 2026. Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd
When was CVE-2026-18321 disclosed?
CVE-2026-18321 was first published in the National Vulnerability Database on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18321 actively exploited?
CVE-2026-18321 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 99.7% of all scored CVEs.
What is the CVSS score of CVE-2026-18321?
CVE-2026-18321 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2026-18321?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18321, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-18321

Explore →

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