Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain low-priv local account
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DeliveryLaunch local race-condition tool
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ExploitRepeatedly trigger Windows Shell shared-resource operation
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ExecutionWin synchronization race window
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ImpactElevate to SYSTEM privileges
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Concurrency control, locking
MITRE ATT&CK
1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires the attacker to already have local, authenticated access to the Windows host with at least low-level user privileges (PR:L) - this is not remotely reachable (AV:L). The attacker must trigger a race condition (CWE-362) in the Windows Shell's handling of a shared resource and win a timing window; high attack complexity (AC:H) means success is probabilistic and typically requires repeated attempts, which limits reliability. No user interaction is needed (UI:N). The primary limiting factors are the mandatory pre-existing local foothold with valid credentials and the non-deterministic race window, which substantially reduce real-world exploitability despite the total technical impact. Hosts patched to the fixed builds (e.g., Server 2025 >=10.0.26100.32690, Win11 24H2 >=10.0.26100.32690, Win10 22H2 >=10.0.19045.7184) are not affected. |
| Impact | This is a legitimate but non-urgent local privilege-escalation issue. The CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.0 HIGH) signals that an attacker must already have local access and low-level (authenticated) privileges, and must win a race window (AC:H) to succeed - meaning exploitation is non-deterministic and not trivially reliable. All real-world exploitation signals point low: EPSS is 0.04% (12th percentile), CISA SSVC records Exploitation:none and Automatable:no, and there is no KEV listing and no public POC. These signals are mutually consistent - low EPSS, no automatability, and no observed exploitation together indicate this is NOT an active or wormable threat. The one signal pulling upward is SSVC Technical Impact:total, which aligns with the C:H/I:H/A:H full-SYSTEM-level compromise that a successful Windows Shell race win would grant. Net assessment: a real but second-tier patch priority - it requires an attacker who already has a foothold with valid credentials, and the high attack complexity plus absence of exploitation evidence place it well below internet-facing or unauthenticated-RCE flaws. Note a metadata conflict: the Tags include 'Information Disclosure' while the Description and CVSS (I:H/A:H) clearly describe privilege elevation, not mere disclosure - treat the EoP framing as authoritative. |
| Exploit ScenarioDerived | An attacker who has already gained a low-privileged authenticated foothold on a Windows host (e.g., via phishing or a standard user account) runs a local tool that repeatedly triggers the vulnerable Windows Shell operation, racing the improper synchronization window to corrupt shared state and gain SYSTEM-level privileges. Because attack complexity is high (AC:H) the exploit must be run many times to win the race, and no public exploit code is currently available, making opportunistic use unlikely. |
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Alert meAnalysisAIv2 – Oct 15, 2026
A race condition (CWE-362) in the Windows Shell lets an attacker who already holds local, low-privileged access on a Windows host win a timing window and elevate to higher privileges on that machine. Affected builds span Windows 10 (1809, 21H2, 22H2), Windows 11 (22H3, 23H2, 24H2, 25H2, 26H1), and Windows Server 2019/2022/2025 including Server Core installations. No public exploit code has been identified at time of analysis and there is no confirmed active exploitation (CISA KEV not listed; SSVC reports Exploitation: none), while EPSS is negligible at 0.04% (12th percentile); Microsoft has released vendor patches via the MSRC update guide.
Earlier versions of this analysis (1)
Windows Shell privilege escalation affects Windows 10 (1809+), Windows 11 (all versions through 26H1), and Windows Server 2019-2025 via a race condition vulnerability (CWE-362). Local authenticated attackers with low-privilege access can exploit concurrent execution flaws to gain SYSTEM-level privileges with low attack complexity and no user interaction required (CVSS 7.8). Vendor-released patches are available for all affected versions. No public exploit identified at time of analysis, though the low complexity and local attack vector make post-patch exploitation attempts likely in enterprise environments with delayed patching cycles.
RemediationAI
Vendor-released patch: Microsoft has published fixes in the MSRC update guide for CVE-2026-27918 at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27918; apply the applicable cumulative update to move each platform to or beyond its fixed build - Windows 10 1809 / Server 2019 / Server 2019 Server Core to 10.0.17763.8644, Windows 10 21H2 to 10.0.19044.7184, Windows 10 22H2 to 10.0.19045.7184, Windows 11 22H3/23H2 to 10.0.22631.6936, Windows 11 24H2 and Server 2025 / Server Core to 10.0.26100.32690, Windows 11 25H2 to 10.0.26200.8246, Windows 11 26H1 to 10.0.28000.1836, Windows Server 2022 to 10.0.20348.5020, and Windows Server 2022 23H2 Edition Server Core to 10.0.25398.2274. Because exploitation requires an existing local, authenticated low-privilege foothold (AV:L/PR:L) and a hard-to-win race window (AC:H), patching can be scheduled on a normal cadence rather than as an emergency; in the interim, reduce the available attack surface by enforcing least privilege so that standard users cannot launch arbitrary local processes or interact with privileged Shell components, tightening local logon rights (for example restricting interactive logon and Remote Desktop access to trusted accounts), and monitoring for anomalous Shell/Explorer process behavior or repeated rapid-firing invocation patterns that would indicate race attempts. Note that privilege restrictions carry operational trade-offs for help-desk and administrative workflows, and they are compensating measures only - they do not replace the vendor update.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 25 packages in microsoft, euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The flaw is a classic race condition (CWE-362) - concurrent execution against a shared resource with improper synchronization - inside the Windows Shell, the user-facing component responsible for the desktop, taskbar, Explorer windows, file-association handling, and inter-process messaging. Because two code paths can interleave incorrectly, an attacker with a valid local session can manipulate timing to cause the Shell to act on data or handles it should not expose to a low-privileged caller, achieving privilege elevation. The CVSS vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H confirms the prerequisites: local access only (AV:L), high attack complexity due to the non-deterministic race window (AC:H), low privileges required (PR:L), and no user interaction (UI:N), with full confidentiality, integrity, and availability impact within the same security scope. The associated tag set also flags an information-disclosure angle, consistent with a Shell race that can leak data across a privilege boundary. Affected CPEs cover Windows 10 Version 1809, 21H2 and 22H2, Windows 11 Versions 22H3, 23H2, 24H2, 25H2 and 26H1, Windows Server 2019, and Windows Server 2019 Server Core Installation; the EUVD record (EUVD-2026-22462) additionally lists Windows Server 2022, Windows Server 2022 23H2 Edition Server Core, and Windows Server 2025 / Server Core builds.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Local-only race condition (AV:L, AC:H) exploitable by an already-authenticated low-priv user (PR:L) yielding full SYSTEM compromise (C:H/I:H/A:H).
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionNVD
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Shell allows an authorized attacker to elevate privileges locally.
Executive ViewAI
A privilege-escalation race condition in the Windows Shell affects a broad cross-section of the organization's Windows 10, Windows 11, and Windows Server 2019/2022/2025 estate, including Server Core builds that anchor many virtualized and data-center workloads. Exploitation requires an attacker to already hold low-privileged local access on a host, so the practical risk is that an existing foothold - from malware, a compromised service account, or an insider - can be converted into administrative control on that machine, enabling lateral movement, credential theft, and persistence. Microsoft has released patches, making this a remediation-discipline problem rather than an emergency, but the breadth of affected builds and the presence of unpatched servers and aging Windows 10 images mean leadership should care about closing the gap before an unrelated intrusion finds an easy escalation path.
Apply vendor patch.
Threat Intelligence Overview
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Race conditions occur when multiple concurrent requests exploit the brief time gap between checking a condition and acting upon it (TOCTOU - Time of Check, Time of Use).
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EUVD-2026-22462
GHSA-r922-wwg3-2m7q
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB