CVE-2026-40378

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-14. the CNA's CVSS baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

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

Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
—
EPSS
53.3%
KEV
Not listed

Published

July 14, 2026

Last Modified

July 22, 2026

Advisory Details (1)

Auto-updated Jul 15, 2026
Patch available. Sources: microsoft.
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40378

Vendor Advisories for CVE-2026-40378(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 25× 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. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 03:30 UTCEG score recompute
  6. 2026-07-19 03:30 UTCVendor advisory
  7. 2026-07-19 03:30 UTCGHSA enrichment
  8. 2026-07-19 02:29 UTCEPSS rescore
  9. 2026-07-18 10:04 UTCEPSS rescore
  10. 2026-07-17 03:44 UTCVendor advisory
  11. 2026-07-17 03:44 UTCGHSA enrichment
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-16 16:02 UTCVendor advisory
  14. 2026-07-16 16:02 UTCGHSA enrichment
  15. 2026-07-16 04:20 UTCVendor advisory
  16. 2026-07-16 04:20 UTCGHSA enrichment
  17. 2026-07-15 16:57 UTCEPSS rescore
  18. 2026-07-15 16:57 UTCEPSS rescore
  19. 2026-07-15 16:38 UTCVendor advisory
  20. 2026-07-15 16:38 UTCGHSA enrichment
  21. 2026-07-15 04:55 UTCVendor advisory
  22. 2026-07-15 04:55 UTCGHSA enrichment
  23. 2026-07-14 17:12 UTCEG score recompute
  24. 2026-07-14 17:12 UTCVendor advisory
  25. 2026-07-14 17:10 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-40378?
CVE-2026-40378 is a high vulnerability published on July 14, 2026. Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.
When was CVE-2026-40378 disclosed?
CVE-2026-40378 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40378 actively exploited?
CVE-2026-40378 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 53.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40378?
CVE-2026-40378 has a CVSS v4.0 base score of 7.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-40378?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40378, 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

Explore the affected products and dependency analysis for CVE-2026-40378

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