EUVD-2026-44255
GHSA-x5vq-pv82-hp56
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local vector requiring an existing low-privilege session (AV:L/PR:L), low complexity with no interaction, and full SYSTEM compromise gives high C/I/A within unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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 (CWE-416 use-after-free) lets an already-authenticated low-privilege user corrupt kernel memory and gain SYSTEM-level control across a broad range of Windows 10, Windows 11, and Windows Server 2016 through 2025 builds. Microsoft self-reported the flaw and has shipped a patch through the Update Guide; there is no public exploit identified at time of analysis and it is not listed in CISA KEV. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to already have local, authenticated access at low privilege (CVSS PR:L, AV:L) on an affected Windows build - i.e. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H describes a low-complexity local attack requiring existing low privileges and no user interaction, yielding full confidentiality, integrity, and availability impact within an unchanged scope - a textbook local privilege-escalation profile scoring 7.8 (High). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who has already gained a low-privileged foothold - for example a standard user session, a compromised service account, or code execution via phishing - runs a crafted program that triggers the kernel use-after-free, grooms pool memory to hijack the dangling object, and escalates to SYSTEM. From SYSTEM they disable security tooling, harvest credentials, and move laterally. … |
| Remediation | Apply the Microsoft security update for CVE-2026-56643 for your specific Windows build - Patch available per vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56643, where the exact KB and patched build for each affected SKU (Windows 10 1607-22H2, Windows 11 24H2-26H1, Server 2016-2025 including Server Core) are listed; no standalone fix version string was provided in the input, so pull the correct KB from that advisory. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: inventory all Windows 10, 11, and Server 2016-2025 systems in scope and prioritize critical infrastructure and sensitive data repositories for patching first. …
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Same weakness CWE-416 – Use After Free
View allSame technique Use After Free
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External POC / Exploit Code
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