Vulnerability details
CVE-2026-40378
Microsoft Windows 10Microsoft Windows 11Microsoft Windows Server
Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability
CVSS 3.1
7.5High
Official description
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 scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (microsoft) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 ≤ v < 10.0.14393.9339 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 ≤ v < 10.0.17763.9020 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 ≤ v < 10.0.19044.7548 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 ≤ v < 10.0.19045.7548 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 ≤ v < 10.0.26100.8875 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 ≤ v < 10.0.26200.8875 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 ≤ v < 10.0.22631.7376 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 ≤ v < 10.0.22631.7376 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 ≤ v < 10.0.28000.2525 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 | 6.2.9200.0 ≤ v < 6.2.9200.26226 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 ≤ v < 6.2.9200.26226 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 ≤ v < 6.3.9600.23291 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 ≤ v < 6.3.9600.23291 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2016 | 10.0.14393.0 ≤ v < 10.0.14393.9339 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 ≤ v < 10.0.14393.9339 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2019 | 10.0.17763.0 ≤ v < 10.0.17763.9020 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 ≤ v < 10.0.17763.9020 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2022 | 10.0.20348.0 ≤ v < 10.0.20348.5386 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2025 | 10.0.26100.0 ≤ v < 10.0.26100.33158 | CVEProject cvelistV5 (CNA) |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 ≤ v < 10.0.26100.33158 | CVEProject cvelistV5 (CNA) |
References and advisories
1- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40378 vendor-advisorypatch
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Details
- Published
- 2026-07-14
- Last updated
- 2026-11-01
- State
- Published
- Assigner (CNA)
- microsoft
Exploit prediction (EPSS)
1.17%
Probability of exploitation in 30 days
67.7%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-789Memory Allocation with Excessive Size Value