CVE-2026-40378 json
Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability
published 2026-07-14 3 mo ago modified 2026-11-01 7 d ago also EUVD-2026-43790
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 67%
- public exploits
- 0
- none known
Summary
Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.
Patch / fix
- Microsoft Windows 10 Version 1607 10.0.14393.9339
- Microsoft Windows 10 Version 1809 10.0.17763.9020
- Microsoft Windows 10 Version 21H2 10.0.19044.7548
- Microsoft Windows 10 Version 22H2 10.0.19045.7548
- Microsoft Windows 11 version 23H2 10.0.22631.7376
- Microsoft Windows 11 Version 24H2 10.0.26100.8875
- Microsoft Windows 11 Version 25H2 10.0.26200.8875
- Microsoft Windows 11 version 26H1 10.0.28000.2525
- Microsoft Windows Server 2012 6.2.9200.26226
- Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.26226
- Microsoft Windows Server 2012 R2 6.3.9600.23291
- Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.23291
- Microsoft Windows Server 2016 10.0.14393.9339
- Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.9339
- Microsoft Windows Server 2019 10.0.17763.9020
- Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.9020
- Microsoft Windows Server 2022 10.0.20348.5386
- Microsoft Windows Server 2025 10.0.26100.33158
- Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.33158
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
1.17% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | 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 |
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
- Microsoft Windows 10 Version 1607
- Microsoft Windows 10 Version 1809
- Microsoft Windows 10 Version 21H2
- Microsoft Windows 10 Version 22H2
- Microsoft Windows 11 version 23H2
- Microsoft Windows 11 Version 24H2
- Microsoft Windows 11 Version 25H2
- Microsoft Windows 11 version 26H1
- Microsoft Windows Server 2012
- Microsoft Windows Server 2012 (Server Core installation)
- Microsoft Windows Server 2012 R2
- Microsoft Windows Server 2012 R2 (Server Core installation)
- Microsoft Windows Server 2016
- Microsoft Windows Server 2016 (Server Core installation)
- Microsoft Windows Server 2019
- Microsoft Windows Server 2019 (Server Core installation)
- Microsoft Windows Server 2022
- Microsoft Windows Server 2025
- Microsoft Windows Server 2025 (Server Core installation)
Classification
- Weakness
-
- CWE-789 Memory Allocation with Excessive Size Value
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-40378
vendor-advisory, patch
Sources
- CVE List CVE-2026-40378
- NVD CVE-2026-40378
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.