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Attack ChainAIDerived

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

  1. Access
    Obtain low-privileged local code execution
  2. Delivery
    Invoke vulnerable Win32 kernel operation
  3. Exploit
    Win TOCTOU race window
  4. Execution
    Read privileged kernel memory
  5. Impact
    Leak data to aid further escalation

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
Exploitation Conditions

Exploitation requires the attacker to already possess authenticated low-privileged local code execution on the target Windows system (AV:L, PR:L) - this is not remotely reachable and requires no victim interaction (UI:N). The core limiting factor is the race condition itself: as a TOCTOU flaw (CWE-367) the attacker must reliably win a narrow timing window between the kernel's check and use of a resource, which the AC:H rating and SSVC 'Automatable: no' confirm is difficult and non-deterministic, likely needing many attempts. Impact is confined to information disclosure (C:H) with no integrity or availability effect, so the realistic payoff is leaked kernel data rather than direct compromise. The specific vulnerable Win32 kernel code path is not named in the available data, so no particular feature or configuration setting can be cited as a prerequisite; it applies to default configurations of the listed in-support Windows versions below the patched build numbers.

Impact

This is a genuinely low-priority issue despite being a kernel vulnerability. The CVSS 3.1 score of 4.7 (Medium) is driven by AV:L (local access required), AC:H (high complexity - winning the TOCTOU race window is non-deterministic), PR:L (the attacker must already have a low-privileged authenticated foothold), and an impact limited strictly to confidentiality (C:H/I:N/A:N) with no scope change (S:U). All signals converge toward low real-world risk rather than conflicting: CISA's SSVC framework rates Exploitation as 'none', Automatable as 'no' (consistent with the race condition that makes AC:H appropriate), and Technical Impact as only 'partial'. There is no CISA KEV listing and no public POC in the provided data, so there is no public exploit identified at time of analysis. No EPSS score was supplied, so quantitative exploitation probability cannot be stated. The one consistency check worth noting: the description says 'disclose information locally' and the vector's AV:L agrees - there is no network/local contradiction here. Net assessment: a defense-in-depth kernel info-disclosure bug most valuable as one link in a larger local exploit chain (e.g., defeating KASLR), not a standalone priority. Patch during normal cycles.

Exploit ScenarioDerived

An attacker who already has the ability to run low-privileged code on a Windows host (e.g., via a standard user account or a compromised low-integrity process) repeatedly triggers the vulnerable Win32 kernel operation to win a narrow time-of-check/time-of-use race window. On a successful race they read kernel memory contents that should be inaccessible, potentially leaking addresses or data useful for a subsequent privilege-escalation chain. The AC:H rating reflects that success is probabilistic and may require many attempts; no public exploit code is identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 13, 2026

Information disclosure in the Windows Win32 Kernel Subsystem stems from a time-of-check time-of-use (TOCTOU) race condition (CWE-367) that lets a local attacker with existing low-privileged code execution leak kernel memory contents. The issue rates only CVSS 4.7 (AV:L/AC:H/PR:L/UI:N, C:H/I:N/A:N) because seizing the narrow check-to-use window is difficult and non-deterministic; CISA's SSVC assessment scores Exploitation as 'none' and Automatable as 'no', and no public exploit code has been identified at time of analysis. Every in-support Windows 10, Windows 11 (21H2 through 26H2) and Windows Server 2012 through 2025 build below its respective patched build number is affected, and Microsoft has published fixes via its update guide.

RemediationAI

Vendor-released patch: Microsoft has shipped fixes for this CVE in its monthly security updates, so apply the applicable build from the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96853 - for example, Windows 10 22H2/21H2 to 10.0.19044.7807, Windows 10 1809 and Server 2019 to 10.0.17763.9376, Windows 10 1607 and Server 2016 to 10.0.14393.9612, Windows 11 23H2 to 10.0.22631.7652, Windows 11 24H2/25H2/26H2 to 10.0.26100.9711, 10.0.26200.9711 and 10.0.26300.9711 respectively, Windows 11 26H1 to 10.0.28000.3231, Server 2012 to 6.2.9200.26434, Server 2012 R2 to 6.3.9600.23470, Server 2022 to 10.0.20348.5761, and Server 2025 to 10.0.26100.33650. No configuration switch or feature can be disabled to remove the vulnerable Win32 kernel path, so compensating controls must target the prerequisite foothold: enforce least privilege, remove unnecessary local accounts, and use WDAC or AppLocker application allowlisting to make it harder for an attacker to first obtain the low-privileged local code execution the race requires, accepting that allowlisting can break line-of-business applications and needs careful staging. Because exploitation is local-only and difficult (AC:H, SSVC Exploitation 'none', Automatable 'no'), priority should follow normal patch cycles rather than emergency action, with elevated urgency only for multi-tenant or shared-workstation environments where untrusted users already run code; there is no indication of active exploitation to justify a different rollout cadence.

Affected VersionsENISA

Windows 10 Version 22H2 10.0.19045.0 <10.0.19044.7807
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7807
Windows 11 Version 26H2 10.0.26300.0 <10.0.26300.9711
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9711
Windows Server 2019 10.0.17763.0 <10.0.17763.9376
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33650
Windows Server 2016 10.0.14393.0 <10.0.14393.9612
Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 <6.3.9600.23470
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.3231
Windows Server 2012 R2 6.3.9600.0 <6.3.9600.23470
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9612
Windows Server 2012 (Server Core installation) 6.2.9200.0 <6.2.9200.26434
Windows Server 2022 10.0.20348.0 <10.0.20348.5761
Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9376
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9612
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9711
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7652
Windows Server 2025 10.0.26100.0 <10.0.26100.33650
Windows Server 2012 6.2.9200.0 <6.2.9200.26434
Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9376

Affected Packages

euvd windows_10_version_1607 fix: 10.0.14393.9612
euvd windows_10_version_1809 fix: 10.0.17763.9376
euvd windows_10_version_21h2 fix: 10.0.19044.7807
euvd windows_10_version_22h2 fix: 10.0.19044.7807
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_2012 fix: 6.2.9200.26434
euvd windows_server_2012_r2 fix: 6.3.9600.23470
euvd windows_server_2012_r2_server_core_installation fix: 6.3.9600.23470
euvd windows_server_2012_server_core_installation fix: 6.2.9200.26434
euvd windows_server_2016 fix: 10.0.14393.9612
euvd windows_server_2016_server_core_installation fix: 10.0.14393.9612
euvd windows_server_2019 fix: 10.0.17763.9376
euvd windows_server_2019_server_core_installation fix: 10.0.17763.9376
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 20 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-367, a time-of-check time-of-use race in a Win32 kernel code path where the check on a resource and its subsequent use are not atomic. Because the check and use are separated in time, a local thread that already holds low-privileged credentials on the machine can repeatedly interleave operations to win the window and cause the kernel to operate on data it should not return, yielding kernel memory disclosure. The CVSS vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N confirms the flaw is local-only (AV:L), requires low privileges (PR:L), needs no user interaction (UI:N), has high complexity (AC:H) due to the race, stays within the same security scope (S:U), and produces high confidentiality impact (C:H) with no integrity or availability effect. The advisory names no specific Win32 feature, syscall, or configuration toggle, so the exposure applies to default installations of the affected Windows builds; exploitation cannot be triggered remotely and does not result from anything the victim does or opens.

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Severity by source

Vendor (microsoft) PRIMARY 4.7 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
vuln.today AI 4.7 MEDIUM

Local-only TOCTOU race requires an authenticated low-priv foothold (AV:L, PR:L) and winning a timing window (AC:H); impact is confidentiality-only kernel info disclosure (C:H, I:N, A:N).

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/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
None
Availability
None

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 20:20 EUVD
CVE Published
Oct 13, 2026 - 19:21 cve.org
MEDIUM 4.7

DescriptionCVE.org

Time-of-check time-of-use (toctou) race condition in Windows Win32 Kernel Subsystem allows an authorized attacker to disclose information locally.

Threat Intelligence Overview

EPSS Score
0.2%
Top 92% exploitable
Prevalence
Ubiquitous
Windows kernel component present across all supported client and server editions
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
5 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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

24
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +24
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

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