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Windows MIDI Service EUVDEUVD-2026-44244

| CVE-2026-56187 HIGH
Use After Free (CWE-416)
2026-07-14 microsoft GHSA-8fq3-vhhq-4r52
7.8
CVSS 3.1 · NVD
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Attack ChainAIDerived

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

  1. Access
    Obtain low-privileged local session
  2. Delivery
    Interact with Windows MIDI Service Module
  3. Exploit
    Trigger use-after-free on freed object
  4. Execution
    Groom heap to control reclaimed memory
  5. Persist
    Hijack control flow via dangling pointer
  6. Impact
    Elevate to higher 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 local, authenticated access with at least low privileges (CVSS PR:L, AV:L) on a Windows 11 host running version 24H2, 25H2, or 26H1 below the patched build, and the ability to reach and interact with the Windows MIDI Service Module to trigger the freed-object dereference. No user interaction is needed (UI:N) and attack complexity is low (AC:L). Limiting factors that reduce realistic risk: the attack cannot be launched remotely (local vector only), it cannot be performed by an unauthenticated actor, it is not automatable per SSVC, and it is confined to the specific Windows 11 servicing branches listed rather than all Windows versions.

Impact

The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.8 High) describes a local-only attack requiring low existing privileges and no user interaction, yielding total confidentiality, integrity, and availability impact within an unchanged scope - a classic elevation-of-privilege profile. Corroborating signals are consistent rather than conflicting: EPSS is low (0.25%, 16th percentile), SSVC reports Exploitation: none and Automatable: no, and no POC or KEV listing is present, so this is not a mass-exploitation candidate. However, SSVC Technical Impact is rated 'total,' matching the C:H/I:H/A:H metrics, meaning successful exploitation fully compromises the affected component. Realistic priority is moderate: it is not an internet-facing, wormable bug, but it is a valuable second-stage EoP primitive for an attacker who already has a local foothold, so it should be patched on the normal-to-expedited Patch Tuesday cadence, prioritized on multi-user and shared endpoints.

Exploit ScenarioDerived

An attacker who has already gained a low-privileged local account or code execution on a Windows 11 endpoint (for example via phishing or a compromised standard-user session) interacts with the MIDI Service Module to trigger the use-after-free, grooming the heap so the freed object is replaced with attacker-controlled data and using the resulting memory corruption to execute code at higher privilege. No user interaction is required and attack complexity is low, but the attacker must first have local access. No public exploit code has been identified at time of analysis.

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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AnalysisAIv2 – Jul 22, 2026

Local privilege escalation in the Windows MIDI Service Module on Windows 11 (versions 24H2, 25H2, and 26H1) allows an already-authenticated low-privileged user to elevate to higher privileges by triggering a use-after-free memory-corruption condition (CWE-416). Reported by Microsoft with a vendor patch already available; there is no public exploit identified at time of analysis and SSVC records exploitation status as none. EPSS is low at 0.25% (16th percentile), consistent with a locally-exploitable EoP that is not yet weaponized.

Earlier versions of this analysis (1)
v1 Jul 14, 2026 - 19:07 CVSS 7.0

Local privilege escalation in the Windows MIDI Service Module affects Windows 11 versions 24H2, 25H2, and 26H1, where a use-after-free (CWE-416) memory corruption lets an already-authorized local user run code with elevated privileges. Microsoft rates it CVSS 7.0 and has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV. Exploitation is non-trivial due to high attack complexity and requires the attacker to already hold low-level local privileges.

RemediationAI

Vendor-released patch: apply the Microsoft cumulative update that raises the build to at least 10.0.26100.8875 (24H2), 10.0.26200.8875 (25H2), or 10.0.28000.2525 (26H1), per the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56187. Since this is delivered through the standard Windows monthly cumulative update, install the latest Patch Tuesday roll-up and reboot to remediate. No Microsoft-published standalone workaround exists for the MIDI Service Module; as compensating controls until patching completes, restrict interactive and low-privilege local logon on sensitive and shared hosts (limiting who can run the code needed to reach the service), and prioritize patching multi-user, kiosk, and shared endpoints where untrusted local accounts exist - with the trade-off that these access restrictions do not neutralize the flaw for legitimate local users and only reduce the population of potential attackers.

Affected VersionsENISA

Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.8875
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.2525
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.8875

Affected Packages

euvd windows_11_version_24h2 fix: 10.0.26100.8875
euvd windows_11_version_25h2 fix: 10.0.26200.8875
euvd windows_11_version_26h1 fix: 10.0.28000.2525

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 3 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 flaw resides in the Windows MIDI Service Module, the operating-system component that handles Musical Instrument Digital Interface (MIDI) device and message routing on Windows 11. The root cause is a use-after-free (CWE-416): a memory object is freed while a dangling reference to it is retained and subsequently dereferenced, letting an attacker who controls the reclaimed allocation corrupt memory and hijack control flow or data. Because the service runs with elevated system context, corrupting its freed objects can translate directly into privilege elevation. The CPE data scopes the issue precisely to Microsoft Windows 11 version 24H2, 25H2, and 26H1 (cpe:2.3:a:microsoft:windows_11_version_24h2 / _25h2 / _26h1).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY HIGH
NVD 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 EoP by an existing low-privileged user (AV:L, PR:L) with no interaction and low complexity; use-after-free in a system service yields full C/I/A impact.

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 VectorNVD

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

Lifecycle Timeline

3
Analysis Updated
Jul 22, 2026 - 12:01 vuln.today
v2 - CVSS changed
CVSS changed
Jul 22, 2026 - 11:52 NVD
7.0 (HIGH) 7.8 (HIGH)
CVE Published
Jul 14, 2026 - 17:09 nvd
HIGH 7.0

DescriptionNVD

Use after free in Windows MIDI Service Module allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

A local privilege escalation vulnerability in Windows 11's MIDI Service Module (CVE-2026-56187) affects users running versions 24H2, 25H2, and 26H1, enabling authenticated users with standard privileges to gain administrative access through a use-after-free memory defect. Although no public exploit has been identified at time of analysis and the 0.3% EPSS score indicates limited near-term weaponization risk, any organization running these Windows 11 versions faces exposure to insider threats and lateral movement from compromised standard accounts. Microsoft has released a patch, making immediate assessment and deployment the priority.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 84% exploitable
Prevalence
Ubiquitous
Windows 11 is deployed across a vast fraction of enterprise and consumer endpoints
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
Scheduled
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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