EUVD-2026-43915
GHSA-jhr9-h6m6-5482
Severity by source
AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Network-reachable but timing-dependent race gives AC:H, an authenticated low-privilege foothold is required so PR:L, and the privilege-escalation outcome yields total C/I/A impact.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Media allows an authorized attacker to elevate privileges over a network.
AnalysisAI
Elevation of privilege in the Windows Media component of Windows 11 (24H2, 25H2, 26H1) and Windows Server 2025 allows an authenticated attacker to win a race condition and gain higher privileges over a network, with total loss of confidentiality, integrity, and availability. The flaw was reported by Microsoft and a patch is available; SSVC currently rates exploitation as none and no public exploit identified at time of analysis. Note a data conflict: the description characterizes this as network privilege escalation while vendor tags label it 'Information Disclosure' - verify intended impact with the MSRC advisory.
Technical ContextAI
The vulnerability is a race condition (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization) in Windows Media, a core multimedia subsystem present across modern Windows client and server builds. Affected products per CPE data are Windows 11 versions 24H2, 25H2, and 26H1, Windows Server 2025, and Windows Server 2025 Server Core installation. Race conditions of this class occur when two or more threads access a shared resource without adequate locking, allowing an attacker who can precisely time concurrent operations to manipulate state during the window between a check and a use, corrupting memory or privilege state in a way the code did not intend.
RemediationAI
Vendor-released patch available: apply the Microsoft security update that brings systems to at least the fixed builds - Windows 11 24H2 to 10.0.26100.8875, Windows 11 25H2 to 10.0.26200.8875, Windows 11 26H1 to 10.0.28000.2269, and Windows Server 2025 and its Server Core installation to 10.0.26100.33158 - as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50398. Because exploitation requires an authenticated network foothold, interim compensating controls where immediate patching is not possible include restricting network access to the affected Windows Media services via host and perimeter firewalls, limiting the set of authenticated accounts that can reach affected hosts, and enforcing least privilege so fewer low-privileged accounts exist to abuse the flaw; note these controls reduce but do not eliminate exposure and may disrupt legitimate media or remote functionality. There is no separately documented feature toggle in the provided data, so patching to the fixed build is the definitive fix.
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Same weakness CWE-362 – Race Condition
View allSame technique Race Condition
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External POC / Exploit Code
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