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Windows Kernel CVE-2026-88141

| EUVDEUVD-2026-100100 HIGH
Use After Free (CWE-416)
2026-10-13 secure@microsoft.com GHSA-c3p4-w9xv-9759
7.0
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain local low-privileged access
  2. Exploit
    Trigger use-after-free race in Windows Kernel
  3. Execution
    Execute attacker code in kernel context
  4. Impact
    Elevate privileges to SYSTEM

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires the attacker to already possess local, authenticated low-privileged code execution on the target Windows system (PR:L, AV:L) - remote exploitation is not possible. No user interaction is needed (UI:N), but the high attack complexity (AC:H) reflects a use-after-free race condition in the kernel that must be won, meaning exploitation may be unreliable and require repeated attempts or specific timing/memory-grooming conditions. No special non-default product feature or configuration is named in the description; any supported, unpatched Windows build in the affected ranges (Windows 11 23H2/24H2/25H2/26H1/26H2 and Windows Server 2022/2025 below the listed fixed builds) is susceptible once local access is obtained.

Impact

This is a credible but not top-tier priority. The CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, score 7.0 HIGH) describes a local-only use-after-free requiring an already-authenticated low-privileged attacker and a high-complexity trigger - consistent with a kernel race condition that is not reliably exploitable on every attempt. Multiple signals agree that this is NOT an imminent, mass-exploitation threat: CISA's SSVC framework records Exploitation=none and Automatable=no (while rating Technical Impact=total, reflecting full kernel compromise if achieved), the CVE is not listed in CISA KEV, and no public proof-of-concept is referenced. EPSS data was not provided in the input, so probabilistic exploitation likelihood cannot be factored in. The signals are internally consistent - high technical impact but low/absent exploitation evidence and high attack complexity - so this reads as a genuinely dangerous-if-exploited local EoP that is currently a patch-on-normal-cycle item rather than an emergency. Note the 'Denial Of Service' tag sits alongside C:H/I:H/A:H full-impact metrics; the primary documented impact is local privilege elevation, not merely DoS.

Exploit ScenarioDerived

An attacker who already has a low-privileged foothold on a Windows host (e.g., via a compromised standard user account or a sandboxed process) runs a local program that manipulates a vulnerable kernel object to trigger the use-after-free, winning a race condition to corrupt kernel memory and execute code at SYSTEM level. No public exploit code is identified at time of analysis, and the high attack complexity means the trigger may require multiple attempts to succeed.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 13, 2026

Local privilege escalation in the Windows Kernel lets an authenticated attacker who already has low-privileged code execution on the host win a use-after-free race condition to obtain SYSTEM-level rights, yielding full compromise of confidentiality, integrity, and availability (CVSS 7.0, CWE-416). Unpatched Windows 11 23H2/24H2/25H2/26H1/26H2 and Windows Server 2022/2025 builds in the ranges listed by Microsoft are affected; the flaw is not remotely reachable, requires local authenticated access, and carries high attack complexity, so exploitation is likely unreliable and may need repeated attempts. No public exploit code has been identified at time of analysis (CISA SSVC exploitation: none, not in KEV), and vendor patches are available, making this a credible but not top-tier priority for most environments.

RemediationAI

Vendor-released patch: Microsoft's update raises affected builds to 10.0.22631.7652 (Windows 11 23H2), 10.0.26100.9711 (24H2), 10.0.26200.9711 (25H2), 10.0.28000.3231 (26H1), 10.0.26300.9711 (26H2), 10.0.20348.5761 (Windows Server 2022), and 10.0.26100.33650 (Windows Server 2025 / Server Core), delivered through Windows Update, WSUS, or the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88141; verify the OS build revision after installation to confirm the fix landed. Because the bug cannot be triggered remotely and requires pre-existing local low-privileged code execution, patch priority is lower than network-facing issues, but multi-user Windows 11 hosts and privileged Windows Server 2022/2025 systems should still be updated promptly. Until patching completes, shrink the local code-execution surface rather than hardening the network edge: enforce WDAC/AppLocker policies that block execution of binaries from user-writable paths (trade-off: unsigned or unmanaged line-of-business apps break unless explicitly authorized), strip unnecessary local administrator rights and use Just Enough Administration (trade-off: help-desk workflows and some admin tooling must be redesigned), and restrict interactive logon, RDP, and scheduled-task creation to trusted accounts (trade-off: convenience loss and possible operational friction). Enable Credential Guard and LSASS protection to limit what a successful attacker can harvest afterward, recognizing these do not prevent the kernel elevation itself. Detect attempts by monitoring for kernel bugchecks (0x50, 0x3B, 0xC2) and anomalous token-elevation events, since high attack complexity means failed exploitation attempts may surface as crashes prior to any successful escalation. No public exploit code or in-the-wild exploitation was identified at time of analysis, so emergency workarounds are not warranted, but unpatched OT/ICS or long-lived embedded Windows systems that cannot be rebuilt quickly should be isolated from untrusted local users.

Affected VersionsENISA

Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9711
Windows Server 2022 10.0.20348.0 <10.0.20348.5761
Windows 11 Version 26H2 10.0.26300.0 <10.0.26300.9711
Windows Server 2025 10.0.26100.0 <10.0.26100.33650
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7652
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9711
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33650
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.3231

Affected Packages

euvd windows_11_version_23h2 fix: 10.0.22631.7652
euvd windows_11_version_24h2 fix: 10.0.26100.9711
euvd windows_11_version_25h2 fix: 10.0.26200.9711
euvd windows_11_version_26h1 fix: 10.0.28000.3231
euvd windows_11_version_26h2 fix: 10.0.26300.9711
euvd windows_server_2022 fix: 10.0.20348.5761
euvd windows_server_2025 fix: 10.0.26100.33650
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33650

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 8 packages in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-416, use-after-free, inside the Windows kernel. A kernel object or pool allocation is released while a stale pointer still references it; if attacker-controlled data is reallocated into that freed slot via heap grooming, the dangling dereference can corrupt kernel structures or redirect a function pointer into code that executes at ring-0, crossing the user/kernel privilege boundary. The authoritative vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H confirms the attacker must already hold local, low-privileged code execution (AV:L, PR:L), that no user interaction is required (UI:N), and that AC:H reflects the timing window and memory-grooming precision needed to win the free/reuse race, which is why real-world exploitation is expected to be flaky rather than a one-shot primitive. Impact remains scope-unchanged (S:U) but total across C/I/A. Per EUVD-2026-100100 the vulnerable code ships across the Windows 11 23H2/24H2/25H2/26H1/26H2 and Windows Server 2022/2025 build branches, including Server Core, with no non-default feature or configuration gate named, so any supported unpatched build in those ranges is susceptible once local access is obtained. Microsoft reported the issue itself (secure@microsoft.com), and the associated tags\u2014Use After Free, Memory Corruption, Denial Of Service\u2014match the crash/bugcheck behavior expected when the race is lost rather than won.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.0 HIGH
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.0 HIGH

Local kernel UAF needs an existing low-priv foothold (AV:L, PR:L) and a hard-to-win race (AC:H); successful kernel compromise yields total C/I/A impact with no scope change.

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 20:20 EUVD
CVE Published
Oct 13, 2026 - 19:21 cve.org
HIGH 7.0

DescriptionCVE.org

Use after free in Windows Kernel allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

A privilege-escalation flaw in the Windows Kernel affects Windows 11 23H2, 24H2, 25H2, 26H1 and 26H2 as well as Windows Server 2022 and 2025, and could allow an attacker who already has a foothold on a machine to escalate to full SYSTEM-level control of that host. The flaw is not remotely reachable and exploitation is complex and likely unreliable, so leadership should treat it as a manageable risk within the existing endpoint and server patch program rather than an emergency. The main organizational impact is on unpatched endpoints and servers where an attacker with any existing low-privilege access could convert that access into complete control of the system and the data on it.

Business Impact: Medium
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 85% exploitable
Prevalence
Ubiquitous
Windows kernel component present across virtually all Windows client and server deployments
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Unlikely
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
Medium
Technical Impact
Total

Priority Score

35
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +35
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

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