CVE-2026-50406

Windows Backup Engine Elevation of Privilege Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 7 High EPSS < 1% KEV · Not listed

Description

Use after free in Windows Backup Engine allows an authorized attacker to elevate privileges locally.

Analysis

Technical impact

The vulnerability is a use‑after‑free condition in the Windows Backup Engine that allows an attacker who already has local system access to execute code with elevated rights beyond those originally granted, leading to privilege escalation. The weakness is classified as CWE‑416.

Affected Systems

The flaw affects Microsoft Windows 10 versions 21H2 and 22H2, and Microsoft Windows 11 versions 24H2, 25H2, and 26H1 on the processor architectures specified in the official CPE entries (x86 for 21H2, x64 for 22H2, arm64 for 24H2 and 25H2, and x64 for 26H1).

Risk and Exploitability

The CVSS score of 7 indicates high severity and the EPSS score of < 1 % reflects a very low current exploitation probability. The vulnerability is not listed in the CISA KEV catalog, indicating no known large‑scale attacks. The flaw is a use‑after‑free in the Windows Backup Engine and requires the attacker to already possess local system access to trigger. The affected Windows versions are 10 21H2 (x86), 10 22H2 (x64), 11 24H2 (arm64), 11 25H2 (arm64), and 11 26H1 (x64), as defined by the official CPE entries.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Microsoft

Windows 10 Version 21H2

affected

Version	Status	Constraints
`10.0.19044.0`	affected	< 10.0.19044.7548

Microsoft

Windows 10 Version 22H2

affected

Version	Status	Constraints
`10.0.19045.0`	affected	< 10.0.19045.7548

Microsoft

Windows 11 Version 24H2

affected

Version	Status	Constraints
`10.0.26100.0`	affected	< 10.0.26100.8875

Microsoft

Windows 11 Version 25H2

affected

Version	Status	Constraints
`10.0.26200.0`	affected	< 10.0.26200.8875

Microsoft

Windows 11 version 26H1

affected

Version	Status	Constraints
`10.0.28000.0`	affected	< 10.0.28000.2525

Configuration 1 [-]

OR	cpe:2.3:o:microsoft:windows_10_21h2:::::::arm64:*
	cpe:2.3:o:microsoft:windows_10_21h2:::::::x64:*
	cpe:2.3:o:microsoft:windows_10_21h2:::::::x86:*
	cpe:2.3:o:microsoft:windows_10_22h2:::::::arm64:*
	cpe:2.3:o:microsoft:windows_10_22h2:::::::x64:*
	cpe:2.3:o:microsoft:windows_10_22h2:::::::x86:*
	cpe:2.3:o:microsoft:windows_11_24h2:::::::arm64:*
	cpe:2.3:o:microsoft:windows_11_24h2:::::::x64:*
	cpe:2.3:o:microsoft:windows_11_25h2:::::::arm64:*
	cpe:2.3:o:microsoft:windows_11_25h2:::::::x64:*
	cpe:2.3:o:microsoft:windows_11_26h1:::::::x64:*
	cpe:2.3:o:microsoft:windows_11_26h1:::::::arm64:*

No data.

Vendor Product Versions

Microsoft

Windows 10 21h2

Version	Status	Scheme	Platform
`[10.0.19044.0,10.0.19044.7548)`	affected	generic	['32-bit_systems', 'arm64-based_systems', 'x64-based_systems']

Microsoft

Windows 10 22h2

Version	Status	Scheme	Platform
`[10.0.19045.0,10.0.19045.7548)`	affected	generic	['32-bit_systems', 'arm64-based_systems', 'x64-based_systems']

Microsoft

Windows 11 24h2

Version	Status	Scheme	Platform
`[10.0.26100.0,10.0.26100.8875)`	affected	generic	['arm64-based_systems', 'x64-based_systems']

Microsoft

Windows 11 25h2

Version	Status	Scheme	Platform
`[10.0.26200.0,10.0.26200.8875)`	affected	generic	['arm64-based_systems', 'x64-based_systems']

Microsoft

Windows 11 26h1

Version	Status	Scheme	Platform
`[10.0.28000.0,10.0.28000.2525)`	affected	generic	['arm64-based_systems', 'x64-based_systems']

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the Microsoft security update for CVE‑2026‑50406 to all affected Windows 10 and Windows 11 installations.
Ensure the Windows Backup service runs under a dedicated, least‑privileged account instead of an administrator account.
Limit local administrator access and implement least‑privilege policies on all user accounts to reduce the impact of a local compromise.

Generated by OpenCVE AI on August 3, 2026 at 03:19 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.279% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50406

History

Jul 15, 2026 3:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Jul 14, 2026 5:45 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Use after free in Windows Backup Engine allows an authorized attacker to elevate privileges locally.
Title		Windows Backup Engine Elevation of Privilege Vulnerability
First Time appeared		Microsoft Microsoft windows 10 21h2 Microsoft windows 10 22h2 Microsoft windows 11 24h2 Microsoft windows 11 25h2 Microsoft windows 11 26h1
Weaknesses		CWE-416
CPEs		cpe:2.3:o:microsoft:windows_10_21H2:::::::x86:* cpe:2.3:o:microsoft:windows_10_22H2:::::::x64:* cpe:2.3:o:microsoft:windows_11_24H2:::::::arm64:* cpe:2.3:o:microsoft:windows_11_25H2:::::::arm64:* cpe:2.3:o:microsoft:windows_11_26H1:::::::x64:*
Vendors & Products		Microsoft Microsoft windows 10 21h2 Microsoft windows 10 22h2 Microsoft windows 11 24h2 Microsoft windows 11 25h2 Microsoft windows 11 26h1
References		https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50406
Metrics		cvssV3_1 `{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}`

Subscriptions

Microsoft Windows 10 21h2 Windows 10 21h2 Windows 10 22h2 Windows 10 22h2 Windows 11 24h2 Windows 11 24h2 Windows 11 25h2 Windows 11 25h2 Windows 11 26h1 Windows 11 26h1

Weaknesses