Microsoft Windows VMSwitch Denial of Service Vulnerability (Microsoft Windows 10 Version 21H2)

CVE-2026-42915

MEDIUM 5.5

At a glance

Source: NVD
EPSS: EPSS 0.38 % · percentile 32 (2026-10-31)
State: PUBLISHED
Published: 2026-06-09 17:06 UTC
Updated: 2026-09-24 13:44 UTC
Assigner: microsoft
NVD status: Modified

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Description

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

Weaknesses (CWE)

CWE-131 — Incorrect Calculation of Buffer Size

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42915

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C	microsoft
CVSS 3.1	MEDIUM 5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	NVD · secure@microsoft.com (Primary)

European references

ENISA EUVD · EUVD-2026-35727
GCVE · GCVE-0-2026-42915

CERT-FR advisories

CERTFR-2026-AVI-0728 — Multiples vulnérabilités dans Microsoft Windows · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* < 10.0.19044.7417
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* < 10.0.19044.7417
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* < 10.0.19044.7417
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* < 10.0.19045.7417
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* < 10.0.19045.7417
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* < 10.0.19045.7417
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* < 10.0.22631.7219
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* < 10.0.22631.7219
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* < 10.0.26100.8655
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* < 10.0.26100.8655
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* < 10.0.26200.8655
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* < 10.0.26200.8655
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:* < 10.0.28000.2269
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:* < 10.0.28000.2269
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* < 10.0.20348.5256
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* < 10.0.26100.32995

Affected products

Product	Versions
Microsoft · Windows 10 Version 21H2	affected 10.0.19044.0 < 10.0.19044.7417
Microsoft · Windows 10 Version 22H2	affected 10.0.19045.0 < 10.0.19045.7417
Microsoft · Windows 11 version 23H2	affected 10.0.22631.0 < 10.0.22631.7219
Microsoft · Windows 11 Version 23H2	affected 10.0.22631.0 < 10.0.22631.7219
Microsoft · Windows 11 Version 24H2	affected 10.0.26100.0 < 10.0.26100.8655
Microsoft · Windows 11 Version 25H2	affected 10.0.26200.0 < 10.0.26200.8655
Microsoft · Windows 11 version 26H1	affected 10.0.28000.0 < 10.0.28000.2269
Microsoft · Windows Server 2022	affected 10.0.20348.0 < 10.0.20348.5256
Microsoft · Windows Server 2025	affected 10.0.26100.0 < 10.0.26100.32995
Microsoft · Windows Server 2025 (Server Core installation)	affected 10.0.26100.0 < 10.0.26100.32995

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD