CVE-2026-18321

MEDIUMPre-NVD 4.74.7—
EchelonGraph scoreMEDIUM 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: 0.1%CVSS: 4.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

CVSS v3
4.7
EG Score
4.7MEDIUMmedium confidence
EG Risk
26
EG Risk 26/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.1%
EPSS %ILE
1st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 31, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Jul 31, 2026
Patch available.
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 rangeFix by version rangeDependents
ntpsec1.2.0+dfsg1-4 ... 1.2.4+dfsg-1 (22 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ntpsec1.2.2+dfsg1-1 ... 1.2.5+dfsg-1 (15 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ntpsec1.2.3+dfsg1-8, 1.2.4+dfsg-1, 1.2.5+dfsg-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ntpsec1.2.3+dfsg1-8, 1.2.4+dfsg-1
  • every version up to 1.2.5+dfsg-1: fixed in 1.2.5+dfsg-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 50× 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.

Showing the most recent 100 of 124 total refreshes for this CVE.

  1. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 06:29 UTCGHSA enrichment
  3. 2026-10-02 16:49 UTCEG score recompute
  4. 2026-10-02 16:49 UTCGHSA enrichment
  5. 2026-10-01 19:49 UTCEPSS rescore
  6. 2026-10-01 02:46 UTCEG score recompute
  7. 2026-10-01 02:46 UTCGHSA enrichment
  8. 2026-09-30 15:02 UTCEPSS rescore
  9. 2026-09-29 06:49 UTCEG score recompute
  10. 2026-09-29 06:49 UTCGHSA enrichment
  11. 2026-09-27 18:42 UTCEG score recompute
  12. 2026-09-27 18:42 UTCGHSA enrichment
  13. 2026-09-27 13:47 UTCEPSS rescore
  14. 2026-09-25 04:52 UTCEG score recompute
  15. 2026-09-25 04:52 UTCGHSA enrichment
  16. 2026-09-24 02:59 UTCEG score recompute
  17. 2026-09-24 02:59 UTCGHSA enrichment
  18. 2026-09-23 05:17 UTCGHSA enrichment
  19. 2026-09-22 07:37 UTCGHSA enrichment
  20. 2026-09-20 21:24 UTCEG score recompute
  21. 2026-09-20 21:24 UTCGHSA enrichment
  22. 2026-09-19 23:41 UTCGHSA enrichment
  23. 2026-09-18 23:13 UTCGHSA enrichment
  24. 2026-09-18 01:33 UTCEG score recompute
  25. 2026-09-18 01:33 UTCGHSA enrichment
Show 75 more
  1. 2026-09-17 03:54 UTCEG score recompute
  2. 2026-09-17 03:54 UTCGHSA enrichment
  3. 2026-09-16 14:07 UTCEPSS rescore
  4. 2026-09-16 05:27 UTCEG score recompute
  5. 2026-09-16 05:27 UTCGHSA enrichment
  6. 2026-09-16 05:14 UTCEPSS rescore
  7. 2026-09-15 03:01 UTCGHSA enrichment
  8. 2026-09-13 19:47 UTCGHSA enrichment
  9. 2026-09-12 22:09 UTCEG score recompute
  10. 2026-09-12 22:09 UTCGHSA enrichment
  11. 2026-09-12 15:00 UTCEPSS rescore
  12. 2026-09-12 00:31 UTCEG score recompute
  13. 2026-09-12 00:31 UTCGHSA enrichment
  14. 2026-09-11 14:52 UTCEPSS rescore
  15. 2026-09-11 09:36 UTCEPSS rescore
  16. 2026-09-11 02:40 UTCEG score recompute
  17. 2026-09-11 02:40 UTCGHSA enrichment
  18. 2026-09-10 09:34 UTCEPSS rescore
  19. 2026-09-10 05:01 UTCGHSA enrichment
  20. 2026-09-09 07:02 UTCGHSA enrichment
  21. 2026-09-07 19:30 UTCEG score recompute
  22. 2026-09-07 19:30 UTCGHSA enrichment
  23. 2026-09-06 13:47 UTCEPSS rescore
  24. 2026-09-06 05:46 UTCEG score recompute
  25. 2026-09-06 05:46 UTCGHSA enrichment
  26. 2026-09-05 08:07 UTCEG score recompute
  27. 2026-09-05 08:07 UTCGHSA enrichment
  28. 2026-09-04 10:29 UTCEG score recompute
  29. 2026-09-04 10:28 UTCGHSA enrichment
  30. 2026-09-04 05:06 UTCEPSS rescore
  31. 2026-09-03 09:07 UTCGHSA enrichment
  32. 2026-09-01 22:31 UTCEG score recompute
  33. 2026-09-01 22:31 UTCGHSA enrichment
  34. 2026-09-01 13:53 UTCEPSS rescore
  35. 2026-08-31 23:24 UTCEG score recompute
  36. 2026-08-31 23:24 UTCGHSA enrichment
  37. 2026-08-30 20:00 UTCGHSA enrichment
  38. 2026-08-29 22:19 UTCEG score recompute
  39. 2026-08-29 22:19 UTCGHSA enrichment
  40. 2026-08-28 21:41 UTCEPSS rescore
  41. 2026-08-28 15:58 UTCGHSA enrichment
  42. 2026-08-27 22:07 UTCEG score recompute
  43. 2026-08-27 22:07 UTCGHSA enrichment
  44. 2026-08-27 14:25 UTCEPSS rescore
  45. 2026-08-27 00:29 UTCEG score recompute
  46. 2026-08-27 00:29 UTCGHSA enrichment
  47. 2026-08-26 14:46 UTCEPSS rescore
  48. 2026-08-26 02:46 UTCEG score recompute
  49. 2026-08-26 02:46 UTCGHSA enrichment
  50. 2026-08-25 13:48 UTCEPSS rescore
  51. 2026-08-25 05:07 UTCEG score recompute
  52. 2026-08-25 05:07 UTCGHSA enrichment
  53. 2026-08-24 07:29 UTCGHSA enrichment
  54. 2026-08-23 09:44 UTCEG score recompute
  55. 2026-08-23 09:44 UTCGHSA enrichment
  56. 2026-08-23 00:19 UTCEPSS rescore
  57. 2026-08-22 12:06 UTCGHSA enrichment
  58. 2026-08-21 14:28 UTCGHSA enrichment
  59. 2026-08-20 16:50 UTCGHSA enrichment
  60. 2026-08-19 19:06 UTCGHSA enrichment
  61. 2026-08-18 20:21 UTCGHSA enrichment
  62. 2026-08-17 22:30 UTCEG score recompute
  63. 2026-08-17 22:30 UTCGHSA enrichment
  64. 2026-08-17 13:47 UTCEPSS rescore
  65. 2026-08-17 00:52 UTCEG score recompute
  66. 2026-08-17 00:52 UTCGHSA enrichment
  67. 2026-08-16 14:56 UTCEPSS rescore
  68. 2026-08-16 03:14 UTCGHSA enrichment
  69. 2026-08-15 05:36 UTCGHSA enrichment
  70. 2026-08-14 07:57 UTCGHSA enrichment
  71. 2026-08-13 10:19 UTCGHSA enrichment
  72. 2026-08-12 12:41 UTCGHSA enrichment
  73. 2026-08-11 15:02 UTCGHSA enrichment
  74. 2026-08-10 17:24 UTCGHSA enrichment
  75. 2026-08-09 19:46 UTCGHSA enrichment

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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 on July 31, 2026, with the most recent update on August 28, 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 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18321?
CVE-2026-18321 has a CVSS base score of 4.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-18321?
A fix for CVE-2026-18321 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-18321 are linked in the Vendor Advisories panel on this page.

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