EUVD-2026-44313
GHSA-v22r-f7j7-wr95
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local authenticated user (AV:L, PR:L) triggers a low-complexity use-after-free for full host compromise, matching the vendor's EoP profile with high C/I/A.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
2DescriptionNVD
Use after free in Desktop Window Manager allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows 11 (version 26H1) Desktop Window Manager (DWM) allows an authenticated low-privileged user to gain SYSTEM-level control by exploiting a use-after-free (CWE-416) memory-corruption flaw. Reported by Microsoft and carrying a CVSS 3.1 score of 7.8, the flaw grants full confidentiality, integrity, and availability impact once triggered locally. There is no public exploit identified at time of analysis, and it is not listed in CISA KEV, but DWM EoP bugs are a historically favored post-compromise primitive.
Technical ContextAI
Desktop Window Manager (dwm.exe / the underlying uDWM and window-compositing components) is the compositing engine responsible for rendering the Windows desktop, visual effects, and window buffers, and it runs with high privilege in the session. CWE-416 (Use After Free) means the code references heap memory that has already been freed - typically because an object's lifetime and reference counting are mishandled - allowing an attacker who can control reallocation of that freed slot to corrupt kernel/service memory and hijack execution flow. The single affected CPE, cpe:2.3:a:microsoft:windows_11_version_26h1, scopes this to the Windows 11 26H1 servicing branch; the tags (Use After Free, Memory Corruption, Denial Of Service) reflect that the same corruption can manifest either as a crash or as controlled privilege elevation.
RemediationAI
Apply the Microsoft-released security update for CVE-2026-58634; a patch is available from the vendor (Patch available per vendor advisory) and the exact fixed build should be taken from the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58634 and deployed through Windows Update / WSUS / your patch-management tooling. Because exploitation requires local authenticated access (PR:L, AV:L), the most effective compensating controls until patching are limiting who can log on interactively - enforce least privilege, restrict local and RDP logon rights, and remove unnecessary standard-user access on high-value hosts - which reduces the pool of accounts that could trigger the flaw but does not eliminate risk from any legitimate local user or malware running in a user session. No reliable non-patch workaround disables DWM safely on modern Windows, since the compositor is integral to the desktop, so prioritizing the official update is the only durable fix.
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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