EUVD-2026-44087
GHSA-2vx4-34hr-q4wv
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local EoP requiring an existing low-privileged foothold (AV:L, PR:L), no user interaction, and a kernel UAF yielding full SYSTEM-level C/I/A impact within unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Kernel allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Microsoft Windows Kernel lets an authenticated attacker who already has low-privileged code execution on a host elevate to SYSTEM by exploiting a use-after-free (CWE-416) memory corruption. It affects a broad range of supported Windows client and server builds - Windows 10 (1809/21H2/22H2), Windows 11 (24H2/25H2/26H1), and Windows Server 2019/2022/2025 - and Microsoft has released a patch. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, so exploitation appears unproven publicly despite the reliably-exploitable nature of kernel UAF flaws.
Technical ContextAI
The flaw resides in the Windows Kernel (ntoskrnl and associated kernel-mode components), the core privileged execution environment that mediates process scheduling, memory management, and object handling for all user-mode code. CWE-416 (Use After Free) means a kernel object is freed but a dangling reference to it is subsequently dereferenced; an attacker who can control the reallocation of that freed memory can groom the pool to place attacker-controlled data where the stale pointer expects a valid object, converting the dangling reference into a controlled read/write or execution primitive in ring 0. Because the vulnerable code runs in kernel context, a successful exploit crosses the user/kernel trust boundary. The affected CPE set spans Windows 10, Windows 11, and Windows Server 2019 through 2025, indicating the vulnerable code is present in a shared, long-lived kernel component rather than a version-specific feature.
RemediationAI
Apply the Microsoft security update for CVE-2026-50478 for your specific Windows SKU and build via Windows Update or WSUS; the patch is available per the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50478 (Patch available per vendor advisory - consult the MSRC page for the exact KB/build number for each affected version). Because this is a kernel memory-corruption bug with no configurable feature to disable, there is no meaningful product-level workaround; compensating controls until patching completes should focus on limiting who can run code on the host: enforce least privilege and remove unnecessary local/interactive logon rights, apply application allowlisting (e.g. WDAC/AppLocker) to block untrusted executables that would provide the required low-privileged foothold, and enable/verify kernel exploit mitigations such as HVCI/Memory Integrity and Kernel-mode Hardware-enforced Stack Protection where supported (trade-off: HVCI can affect older third-party drivers and requires compatible hardware). Prioritize patching internet-facing and multi-user/RDP hosts where untrusted low-privileged code is most likely to run.
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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