CVE-2026-40378 | BDVDB-2026-347703 Detail

MicrosoftWindows 10 Version 1607

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.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact high. Attack vector: network.

Weaknesses#

CWE-789 Memory Allocation with Excessive Size Value

References#

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

Exploit#

No public exploit known

History#

Version 12026-07-14Record published in the CVE List.
Version 22026-11-10Most recent update recorded in the CVE List.

Published

Published: 2026-07-14
Last modified: 2026-11-10

Vendor information

Vendor: Microsoft
Product: Windows 10 Version 1607

All Microsoft vulnerabilities

Score

7.5 High

EPSS

1.1%, Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 67.8.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 10.0.14393.0 and < 10.0.14393.9339
Fixed
10.0.14393.9339

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.5 High

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	None
Integrity	None
Availability	High

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).