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Windows DWM CVE-2026-83726

| EUVDEUVD-2026-99347 HIGH
Use After Free (CWE-416)
2026-10-13 secure@microsoft.com GHSA-62vm-j75h-w8q6
7.8
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 low-privileged local access
  2. Delivery
    Launch crafted process targeting DWM Core
  3. Exploit
    Trigger use-after-free (CWE-416)
  4. Execution
    Corrupt freed memory to hijack execution
  5. Impact
    Gain SYSTEM-level privileges

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

Exploitation requires the attacker to already possess authenticated local access to the target host at standard (low) privilege - per the CVSS vector PR:L and AV:L - and the ability to execute code that interacts with the Windows DWM (Desktop Window Manager) Core Library, which is present and running by default on all supported Windows editions. No user interaction is required (UI:N) and no special or non-default configuration is needed, since DWM is a default-enabled graphics subsystem. The key limiting factor is the local-access prerequisite: this cannot be exploited remotely or by an unauthenticated attacker, so it functions as a post-foothold escalation step rather than an entry point. Affected builds are the pre-patch versions enumerated in EUVD (e.g., Windows 11 24H2 below 10.0.26100.9711, Server 2025 below 10.0.26100.33650); patched builds are not exploitable.

Impact

This is a credible but second-tier priority: a high-severity local elevation-of-privilege flaw rather than a remotely exploitable crisis. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N) confirms the attacker must already have local access with low (standard user) privileges, but exploitation is low-complexity with no user interaction and yields full confidentiality, integrity, and availability impact (C:H/I:H/A:H) - consistent with CWE-416 use-after-free memory corruption that typically escalates to SYSTEM. The signals are mutually consistent and lean AWAY from emergency patching: CISA SSVC rates Exploitation as 'none' and Automatable as 'no', meaning no observed exploitation and no reliable mass-automation, though Technical Impact is 'total'. There is no CISA KEV listing and no POC reported, so exploitation status is 'no public exploit identified at time of analysis'. No EPSS score was provided, so probabilistic exploitation likelihood could not be weighed. The practical takeaway: because this requires a foothold on the host first, it is a post-compromise privilege-escalation chain-link rather than an initial-access threat, and SSVC's 'no active exploitation' should be treated as a point-in-time status for a recently disclosed Microsoft bug that could change.

Exploit ScenarioDerived

An attacker who already has a low-privileged foothold on a Windows host - for example via phishing-delivered malware or a compromised standard user account - runs a crafted program that interacts with the Desktop Window Manager (DWM) Core Library to trigger the use-after-free, corrupting kernel/component memory to execute code at SYSTEM. No user interaction is needed and attack complexity is low, making this a reliable second-stage privilege escalation. No public exploit code has been identified at the time of analysis, so a working exploit would currently have to be developed by the attacker.

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 14, 2026

Local privilege escalation in the Windows Desktop Window Manager (DWM) Core Library allows an authenticated attacker holding standard user rights on a host to corrupt the DWM process through a use-after-free and execute code with the elevated privileges that process enjoys. Exploitation requires prior local access at low privilege (CVSS AV:L/PR:L), needs no user interaction and no non-default configuration, because DWM is a default-enabled composition subsystem on every supported Windows 10, Windows 11, and Windows Server build listed by EUVD. Microsoft has published fixed builds and no public exploit has been identified at time of analysis, so this functions as a post-foothold escalation step rather than a remote entry point; severity is high (7.8) but it is not a remotely exploitable crisis.

RemediationAI

Apply the vendor patch distributed through Microsoft Update / Windows Update; patch availability is confirmed ("Available from vendor"), and the fixed builds to verify against are 10.0.14393.9612 (Windows 10 1607 / Server 2016 and Server Core), 10.0.17763.9376 (Windows 10 1809 / Server 2019 and Server Core), 10.0.19044.7807 (Windows 10 21H2 and 22H2 as published by EUVD), 10.0.22631.7652 (Windows 11 23H2), 10.0.26100.33650 (Server 2025 and Server Core) and 10.0.26100.9711 (Windows 11 24H2), 10.0.26200.9711 (Windows 11 25H2), 10.0.26300.9711 (Windows 11 26H2), 10.0.28000.3231 (Windows 11 26H1), and 10.0.20348.5761 (Server 2022); consult https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83726 for the authoritative per-build KB mapping, since the update guide remains the source of truth over any third-party ceiling figure. There is no practical feature-level workaround: DWM is a mandatory, always-on composition subsystem, and the legacy DisableDwm value under HKLM\SOFTWARE\Microsoft\Windows\Dwm is unsupported on Windows 8 and later, typically ignored, and would break composited UI, DPI scaling, and many modern applications even if honored. Because the assessed prerequisite is that the attacker already holds low-privilege local access, the effective compensating controls are access-reducing and detection-oriented: enforce least privilege and remove unnecessary local administrator or interactive-logon rights, restrict RDP and console access to trusted users, and constrain what untrusted users can execute via AppLocker or WDAC policies (trade-off: allow-listing requires maintenance and can block legitimate software). Monitor for dwm.exe process crashes and WerFault minidumps and for Windows Application log crash events as a possible exploitation indicator, since a failed or partial UAF attempt frequently surfaces as a DWM crash before any privilege gain, and note that SSVC rates exploitation as "none" and automatable as "no", so patching can follow normal priority rather than emergency change control.

Affected VersionsENISA

Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9376
Windows Server 2025 10.0.26100.0 <10.0.26100.33650
Windows Server 2022 10.0.20348.0 <10.0.20348.5761
Windows Server 2016 10.0.14393.0 <10.0.14393.9612
Windows Server 2019 10.0.17763.0 <10.0.17763.9376
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7807
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9711
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 10 Version 22H2 10.0.19045.0 <10.0.19044.7807
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9612
Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9376
Windows 11 Version 26H2 10.0.26300.0 <10.0.26300.9711
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.3231
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9612
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33650

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_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 16 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 Desktop Window Manager Core Library (dwmcore.dll) is the compositing engine that renders and manages windows on modern Windows; DWM runs by default on every supported edition and executes with privileges above those of an ordinary standard-user process, which is precisely why memory-safety defects inside it translate into elevation of privilege. The root cause here is CWE-416, Use After Free: an object allocated in the DWM heap is freed while a dangling reference to it remains, and the attacker who can influence the timing or contents of that freed block can re-use the memory and obtain attacker-influenced data or control flow inside the DWM process. The provided tags (Use After Free, Memory Corruption, Denial Of Service) are consistent with that class - an uncontrolled UAF typically yields either a crash of dwm.exe (availability impact) or, with heap grooming, arbitrary code execution in the victim process. The vulnerable surface is local and interactive in nature (AV:L/AC:L/PR:L/UI:N/S:U), so the attacker must already be running code on the target host and then arrange interaction with the composition subsystem; the assessed vector confirms this is a low-complexity, low-privilege local attack with unchanged scope and high confidentiality, integrity, and availability impact. Affected builds per EUVD include Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (23H2, 24H2, 25H2, 26H1, 26H2), and Windows Server 2016, 2019, 2022, and 2025 (including Server Core installations); patched builds are not exploitable.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.8 HIGH

Local-only use-after-free needing a standard-user foothold gives AV:L and PR:L; it is reliably triggerable (AC:L) with no interaction, yielding full SYSTEM impact (C/I/A:H).

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:L/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
Low
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 - 19:20 cve.org
HIGH 7.8

DescriptionCVE.org

Use after free in Windows DWM Core Library allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

A privilege-escalation flaw in the Windows Desktop Window Manager (DWM) Core Library affects the default graphical subsystem present on every supported Windows 10, Windows 11, and Windows Server build, meaning essentially the entire Windows endpoint and server estate is in scope. Because exploitation requires an attacker to already hold a standard user account on the machine and yields the elevated rights of the DWM process, the practical risk is that any commodity malware, phishing payload, or malicious insider can turn a low-privilege beachhead into full administrative control of the host, enabling credential theft, data exfiltration, and lateral movement. Leadership should treat this as a fleet-wide patch-management obligation rather than an emergency, since Microsoft has released fixed builds, no public exploit code has been identified, and there is no remote attack path.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 77% exploitable
Prevalence
Ubiquitous
DWM Core is a built-in component of all supported Windows 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 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
High
Technical Impact
Total

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
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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