CVE-2026-42915 | Microsoft Windows VMSwitch Denial of Service Vulnerability

Incorrect calculation of buffer size in Windows VMSwitch allows an authorized attacker to deny service locally.

Published: 2026-06-09 Last update: 2026-06-19 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2026-42915

EPSS CVSS CWE GHSA Affected

Conclusion & alert: CVE-2026-42915 is rated Low Risk (31.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.35%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-42915

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-20	0.52%	0.35%	-0.17%
2	2026-06-15	0.21%	0.52%	+0.31%
3	2026-06-10	—	0.21%	—

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-42915

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Weakness enumeration for CVE-2026-42915

CWE-131 MITRE ↗

GitHub Security Advisory for CVE-2026-42915

GHSA-3pg4-4j29-q4rr · Severity: medium — Incorrect calculation of buffer size in Windows TCP/IP allows an authorized attacker to deny...

Affected software / configurations for CVE-2026-42915

Vendor	Product	Version	Raw CPE
microsoft	windows_server_2022	>= 10.0.20348.0, < 10.0.20348.5256	cpe:2.3:o:microsoft:windows_server_2022::::::::
microsoft	windows_10_21H2	>= 10.0.19044.0, < 10.0.19044.7417	cpe:2.3:o:microsoft:windows_10_21H2:::::::x86:*
microsoft	windows_10_22H2	>= 10.0.19045.0, < 10.0.19045.7417	cpe:2.3:o:microsoft:windows_10_22H2:::::::x64:*
microsoft	windows_server_2025	>= 10.0.26100.0, < 10.0.26100.32995	cpe:2.3:o:microsoft:windows_server_2025::::::::
microsoft	windows_11_25H2	>= 10.0.26200.0, < 10.0.26200.8655	cpe:2.3:o:microsoft:windows_11_25H2:::::::arm64:*
microsoft	windows_11_23H2	>= 10.0.22631.0, < 10.0.22631.7219	cpe:2.3:o:microsoft:windows_11_23H2:::::::arm64:*
microsoft	windows_11_23H2	>= 10.0.22631.0, < 10.0.22631.7219	cpe:2.3:o:microsoft:windows_11_23H2:::::::x64:*
microsoft	windows_11_24H2	>= 10.0.26100.0, < 10.0.26100.8655	cpe:2.3:o:microsoft:windows_11_24H2:::::::arm64:*
microsoft	windows_11_26H1	>= 10.0.28000.0, < 10.0.28000.2269	cpe:2.3:o:microsoft:windows_11_26H1:::::::x64:*

References for CVE-2026-42915

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42915	Vendor Advisory

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