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Windows DHCP Server EUVDEUVD-2026-73571

| CVE-2026-69637 MEDIUM
Out-of-bounds Read (CWE-125)
2026-09-08 secure@microsoft.com GHSA-vfx6-9m7w-9xrc
5.7
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
    Gain authorized adjacent network access
  2. Delivery
    Send malformed DHCP request packet
  3. Exploit
    Trigger out-of-bounds read in DHCP service
  4. Execution
    DHCP service process crashes
  5. Impact
    Denial of service to all network clients on segment

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

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 be adjacent to the target on the same Layer-2 network segment or VLAN (AV:A) and to hold low-privilege authorized access to that network (PR:L); pure unauthenticated drive-by exploitation is not possible per the CVSS vector. The Windows DHCP Server role must be actively installed and running on the target host. No user interaction is required (UI:N). Internet-based remote attackers cannot directly reach the DHCP service without first achieving network adjacency, such as through a VPN connection, compromised host pivot, or physical access to the network. The vulnerability does not require any non-default DHCP Server configuration - the default installed role is sufficient.

Impact

The CVSS 5.7 score is well-calibrated for this vulnerability. The adjacent-only attack vector (AV:A), low-privilege requirement (PR:L), and pure availability impact (C:N/I:N/A:H) collectively constrain real-world risk. An attacker cannot reach the DHCP service from the open internet without first achieving network adjacency, and must hold some form of authorized network access. That said, in enterprise environments the business impact of DHCP service loss is high: a crash denies network connectivity to all clients on the affected segment until the service is restarted or failover activates. No EPSS score was provided in the input data, and the vulnerability is absent from the CISA KEV catalog, suggesting opportunistic mass exploitation is unlikely. The absence of public POC code further supports a lower near-term exploitation probability. The 'Buffer Overflow' and 'Information Disclosure' tags in the input metadata are both inaccurate - the CWE is an out-of-bounds read (not a write/overflow), and the CVSS vector confirms no confidentiality impact - so these signals should be disregarded for triage purposes.

Exploit ScenarioDerived

An authorized attacker already present on the same LAN segment or VLAN as a vulnerable Windows DHCP Server sends a specially crafted malformed DHCP request packet designed to trigger the out-of-bounds read in the server's packet processing routine. The DHCP service crashes or hangs, immediately denying IP address assignment to all clients on the segment until an administrator restarts the service. No public exploit code has been identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.6% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 09, 2026

Out-of-bounds read (CWE-125) in the Windows DHCP Server service allows an authorized adjacent-network attacker to crash the DHCP service, causing a denial of service that disrupts IP address assignment for all clients depending on that server. The vulnerability affects a broad swath of Windows Server releases from 2012 through 2025 with the DHCP Server role installed. No public exploit code or active exploitation (CISA KEV) has been identified at time of analysis; Microsoft has released patches addressing all affected build lines.

RemediationAI

Apply the Microsoft-released patches for this CVE targeting the following fixed builds: Windows Server 2012 to 6.2.9200.26349 or later, Windows Server 2012 R2 to 6.3.9600.23397 or later, Windows Server 2016 to 10.0.14393.9512 or later, Windows Server 2019 to 10.0.17763.9245 or later, Windows Server 2022 to 10.0.20348.5622 or later, and Windows Server 2025 to 10.0.26100.33438 or later. Consult the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69637 for package details. As a compensating control prior to patching, enforce VLAN segmentation or firewall ACLs to restrict DHCP server UDP ports (67/68) to only trusted client subnets, reducing exposure to the adjacent-only attack vector. Where available, enabling Windows DHCP Server failover or HA pairing can reduce client-facing availability impact if the primary server crashes. Note that blocking DHCP traffic broadly will itself disrupt client connectivity, so apply such controls with care in production environments.

Affected VersionsENISA

Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9245
Windows Server 2012 R2 6.3.9600.0 <6.3.9600.23397
Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9245
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9512
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9512
Windows Server 2012 6.2.9200.0 <6.2.9200.26349
Windows Server 2016 10.0.14393.0 <10.0.14393.9512
Windows Server 2025 10.0.26100.0 <10.0.26100.33438
Windows Server 2019 10.0.17763.0 <10.0.17763.9245
Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 <6.3.9600.23397
Windows Server 2022 10.0.20348.0 <10.0.20348.5622
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33438
Windows Server 2012 (Server Core installation) 6.2.9200.0 <6.2.9200.26349

Affected Packages

euvd windows_10_version_1607 fix: 10.0.14393.9512
euvd windows_10_version_1809 fix: 10.0.17763.9245
euvd windows_server_2012 fix: 6.2.9200.26349
euvd windows_server_2012_r2 fix: 6.3.9600.23397
euvd windows_server_2012_r2_server_core_installation fix: 6.3.9600.23397
euvd windows_server_2012_server_core_installation fix: 6.2.9200.26349
euvd windows_server_2016 fix: 10.0.14393.9512
euvd windows_server_2016_server_core_installation fix: 10.0.14393.9512
euvd windows_server_2019 fix: 10.0.17763.9245
euvd windows_server_2019_server_core_installation fix: 10.0.17763.9245
euvd windows_server_2022 fix: 10.0.20348.5622
euvd windows_server_2025 fix: 10.0.26100.33438
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33438

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 13 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 Server is an optional Windows Server role that manages IP address leasing and network configuration for LAN clients via the DHCP protocol. CWE-125 (Out-of-Bounds Read) indicates the server reads past the end of an allocated memory buffer when processing DHCP protocol messages, likely a malformed or oversized packet field. This results in an unhandled exception that terminates or crashes the DHCP service process. The adjacent attack vector (AV:A) correctly reflects that DHCP broadcast traffic is typically bounded by Layer-2 network segments or VLANs, preventing direct internet exploitation without network adjacency. Affected CPE ranges span Windows Server 2012 (6.2.9200), 2012 R2 (6.3.9600), 2016 (10.0.14393), 2019 (10.0.17763), 2022 (10.0.20348), and 2025 (10.0.26100), plus Windows 10 versions 1607 and 1809 when the DHCP Server feature is enabled.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 5.7 MEDIUM
AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI 5.7 MEDIUM

Adjacent-only DHCP protocol, low privilege (authorized network user), no confidentiality or integrity impact, crash causes high availability loss.

3.1 AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:19 cve.org
MEDIUM 5.7

DescriptionCVE.org

Out-of-bounds read in Windows DHCP Server allows an authorized attacker to deny service over an adjacent network.

Threat Intelligence Overview

EPSS Score
0.6%
Top 51% exploitable
Prevalence
High
widely deployed DHCP role across enterprise Windows Server environments
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 0.6%
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
Scheduled
Exploitation
None
System Exposure· derived
Controlled
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0
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