EUVD-2026-43868
GHSA-4wcj-v4hp-ch6p
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local privilege escalation requiring existing low-privileged access (AV:L, PR:L), no user interaction, low complexity, yielding full SYSTEM-level confidentiality, integrity, and availability impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Unified Consent System allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Unified Consent System (UCS) lets an already-authenticated attacker exploit a use-after-free memory-corruption flaw (CWE-416) to gain higher privileges, potentially up to SYSTEM. It affects a broad range of current Windows client and server builds including Windows 10 21H2/22H2, Windows 11 24H2/25H2/26H1, and Windows Server 2025. Reported by Microsoft with a CVSS 3.1 base score of 7.8; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The flaw is a use-after-free (CWE-416) in the Windows Unified Consent System, the platform component responsible for mediating and brokering user/application consent decisions. A use-after-free occurs when code continues to reference memory that has already been freed, allowing an attacker who can control the timing of allocation and reuse to place attacker-influenced data into the freed object and hijack subsequent pointer or object dereferences. Because UCS operates as a privileged local component, controlling a freed object during a consent operation can lead to execution in a higher-privilege context. The CPE data confirms this is an operating-system-level defect spanning Windows 10 (21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2025 (including Server Core), rather than an add-on application.
RemediationAI
Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-50326 from the Security Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50326, selecting the KB/build that matches each affected edition (Windows 10 21H2/22H2, Windows 11 24H2/25H2/26H1, Windows Server 2025 and Server Core). Because the exact patched build numbers are enumerated per-product in the MSRC portal rather than provided here, confirm the specific KB for your build; the fix version is not independently reproduced in this analysis. As this is a local elevation-of-privilege bug with no documented pre-patch workaround, the primary compensating control until patching is to limit who can execute code on the host: enforce least-privilege accounts, restrict local/interactive logon rights, apply application allowlisting (WDAC/AppLocker) to prevent untrusted binaries from running the exploitation primitive, and prioritize patching on multi-user, RDP-exposed, and terminal/session hosts where untrusted low-privilege users are most likely present. These controls reduce the pool of potential local attackers but do not remove the underlying flaw.
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Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today