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Windows DHCP Client CVE-2026-61361

| EUVDEUVD-2026-56322 HIGH
Use After Free (CWE-416)
2026-08-11 secure@microsoft.com GHSA-xrgh-3p8w-6q6r
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 authorized local session on target host
  2. Delivery
    Identify timing window in DHCP Client UAF code path
  3. Exploit
    Trigger race condition to free heap object
  4. Execution
    Control heap reallocation to place attacker data
  5. Persist
    Access freed pointer redirects execution
  6. Impact
    Execute arbitrary code at DHCP Client privilege level

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 an authorized local account (PR:L) - anonymous or remote network access is not sufficient per the AV:L vector. The attacker must already have the ability to execute code locally on the affected Windows 11 or Windows Server 2025 host. High attack complexity (AC:H) further constrains exploitation: triggering the use-after-free likely depends on a timing-sensitive race condition, meaning exploitation is not trivially reproducible. Systems where the DHCP Client service is disabled (e.g., hosts with static IP configuration) are not exposed to this vulnerability. What limits exploitation: the requirement for a pre-existing authorized local session, race-condition dependency raising the exploitation bar, and the absence of any confirmed public exploit or widespread exploitation campaigns at time of analysis.

Impact

CVSS 7.0 with vector AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H reflects a bounded but meaningful threat. The local attack vector eliminates remote unauthenticated exploitation entirely; combined with high attack complexity (AC:H), reliable exploitation likely requires controlled timing or environment-specific conditions. The 'Denial Of Service' tag alongside 'Use After Free' in the source intelligence suggests a crash is the more consistently achievable outcome, while arbitrary code execution may demand an additional exploitation primitive - this is inferred from tag data and AC:H, not independently confirmed. The CVE does not appear in the CISA KEV catalog and no public exploit code has been identified, further depressing near-term exploitation probability. For well-access-controlled environments enforcing least-privilege local logon, real-world risk is moderate; shared-user systems or VDI environments where multiple authorized users share a host face higher exposure. No EPSS score was provided in the source data - exploitation probability is inferred as low-to-moderate based on AC:H and absence of KEV or POC.

Exploit ScenarioDerived

An authorized local user on an unpatched Windows 11 or Server 2025 system crafts a sequence of operations against the DHCP Client service designed to trigger a race condition, causing the service to access a freed heap buffer. By winning the race and controlling the memory reuse (e.g., via heap spray or allocation shaping), the attacker redirects execution flow to arbitrary code running at the DHCP Client service's privilege level. No public exploit has been identified at time of analysis, and AC:H indicates reliable exploitation requires non-trivial engineering.

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 – Aug 11, 2026

Local code execution in the Windows DHCP Client exposes Windows 11 and Windows Server 2025 systems to privilege escalation by authorized local users via a use-after-free memory corruption condition. The flaw (CWE-416) requires high attack complexity - consistent with race-condition-dependent UAF exploitation - and an existing local foothold (PR:L, AV:L), limiting its practical reach compared to its full C:H/I:H/A:H impact triad. No public exploit has been identified at time of analysis, and Microsoft has released a vendor-confirmed patch.

RemediationAI

Apply the Microsoft security update documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-61361. Fixed builds confirmed via EUVD-2026-56322 are: Windows Server 2025 (Standard and Server Core) build 10.0.26100.33296 or later; Windows 11 24H2 build 10.0.26100.9168 or later; Windows 11 25H2 build 10.0.26200.9168 or later; and Windows 11 26H1 build 10.0.28000.2704 or later. If immediate patching is not feasible, enforce least-privilege local logon access to limit which accounts can trigger the vulnerable code path - this raises the bar since PR:L access is required. On systems configured with static IP addresses, disabling the DHCP Client service (via services.msc or Group Policy) would eliminate the attack surface entirely, though this disrupts automatic network configuration and is not viable in most enterprise environments. Monitor Windows Event Logs and crash dumps for unexpected DHCP Client (Dhcpsvc) service crashes as an indicator of exploitation attempts.

Affected VersionsENISA

Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33296
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9168
Windows Server 2025 10.0.26100.0 <10.0.26100.33296
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.2704
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9168

Affected Packages

euvd windows_11_version_24h2 fix: 10.0.26100.9168
euvd windows_11_version_25h2 fix: 10.0.26200.9168
euvd windows_11_version_26h1 fix: 10.0.28000.2704
euvd windows_server_2025 fix: 10.0.26100.33296
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33296

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 5 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 Windows DHCP Client is a built-in Windows service responsible for dynamically obtaining IP address and network configuration via the DHCP protocol. CWE-416 (Use After Free) identifies the root cause: the service accesses a heap memory region after it has been freed, allowing an attacker who controls the memory reuse to redirect program execution. UAF vulnerabilities in multi-threaded network client services frequently depend on precise timing to win a race between free and reuse operations, which is consistent with the CVSS AC:H designation. The local attack vector (AV:L) confirms exploitation cannot be triggered remotely over the network - the attacker must already have code execution or an interactive session on the host. Affected products identified via EUVD-2026-56322 span CPE-range entries for Windows 11 (24H2, 25H2, 26H1) and Windows Server 2025 (both standard and Server Core installations) in the 10.0.26100.x and 10.0.28000.x build families.

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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

AV:L confirmed by description; PR:L because 'authorized attacker' requires an existing local account; AC:H consistent with UAF race-condition exploitation; full C/I/A:H reflects arbitrary code execution potential.

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:P/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
Aug 11, 2026 - 18:19 EUVD
CVE Published
Aug 11, 2026 - 17:18 cve.org
HIGH 7.0

DescriptionCVE.org

Use after free in Windows DHCP Client allows an authorized attacker to execute code locally.

Executive ViewAI

Why It Matters

A local privilege escalation vulnerability in the Windows DHCP Client affects Windows 11 and Windows Server 2025 systems, allowing authenticated local users to escalate permissions to SYSTEM level through a use-after-free memory flaw. This exposes organizations to unauthorized privilege escalation and potential lateral movement by insiders or attackers with local foothold access.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 83% exploitable
Prevalence
High
Windows 11 and Server 2025 are widely deployed enterprise endpoint and server platforms
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Unlikely
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

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.

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