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Wired AutoConfig Service CVE-2026-85829

| EUVDEUVD-2026-99538 HIGH
Double Free (CWE-415)
2026-10-13 secure@microsoft.com GHSA-j87g-pwch-g889
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 authenticated local user session
  2. Exploit
    Interact with Wired AutoConfig (dot3svc) service
  3. Execution
    Trigger double free (CWE-415) corrupting memory
  4. Impact
    Execute arbitrary code with SYSTEM privileges

Vulnerability Assessment

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

Requires the attacker to already hold an authenticated, low-privileged local account or session on the target Windows host (AV:L, PR:L) - this is a post-access escalation, not a remote entry point. The vulnerable component is the Wired AutoConfig service (dot3svc), which manages IEEE 802.1X authentication for wired Ethernet and is present on all supported Windows 10/11 and Windows Server builds listed in the EUVD data. No user interaction is needed (UI:N) and complexity is low (AC:L). The primary limiting factors are the need for prior local authenticated access and the requirement to reach/interact with the dot3svc service; remote or unauthenticated exploitation is not possible per the vendor CVSS vector.

Impact

This is a credible but not emergency-tier local privilege escalation. The CVSS 3.1 vector (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.8) describes a locally-exploitable, low-complexity flaw requiring low privileges (PR:L) and no user interaction, yielding full confidentiality, integrity and availability impact - consistent with a CWE-415 double free in a Windows service that can be driven to code execution at SYSTEM. The signals are mutually consistent and point to moderate real-world urgency rather than crisis: CISA's SSVC decision framework records Exploitation=none and Automatable=no, meaning no observed exploitation and no reliable mass-automation path, though Technical Impact=total agrees with the C:H/I:H/A:H rating. There is no KEV listing and no POC referenced, so per the available data this is 'no public exploit identified at time of analysis.' EPSS is NOT provided in the input, so exploitation probability cannot be quantified here. Because the attack vector is local and requires an already-authenticated foothold, this is a post-compromise escalation primitive - valuable to an attacker who already has a user-level session, but not a remote entry point. Prioritize via normal Microsoft patch cycles, elevated for multi-user or shared Windows hosts where untrusted users hold local accounts.

Exploit ScenarioDerived

An attacker who already has a low-privileged authenticated session on a Windows host (via phishing foothold, stolen credentials, or a standard user account on a shared machine) locally interacts with the Wired AutoConfig (dot3svc) service to trigger the double free, corrupting memory to gain code execution as SYSTEM. No user interaction is required (UI:N) and attack complexity is low (AC:L), but the attacker must first possess local access and valid privileges (AV:L/PR:L). No public exploit is 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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AnalysisAIv1 – Oct 13, 2026

Local privilege escalation in the Microsoft Windows Wired AutoConfig Service (dot3svc) allows an attacker who already holds a low-privileged authenticated session on a Windows host to elevate to SYSTEM-level privileges by triggering a double-free memory corruption in the service. The flaw (CWE-415, CVSS 3.1 base 7.8, vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) affects the full range of supported Windows 10, Windows 11, and Windows Server releases enumerated in the EUVD data, including Server 2012 through Server 2025. Microsoft has published a vendor patch (MSRC update guide for CVE-2026-85829); CISA's SSVC assessment rates exploitation as 'none' and automatable as 'no', and no public exploit code has been identified at time of analysis, so this is a post-access escalation risk rather than a wormable or remote-entry issue.

RemediationAI

Vendor-released patch: apply the Microsoft security update for CVE-2026-85829 as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85829, which lifts affected hosts to the fixed builds 10.0.14393.9612 (Windows 10 1607 / Server 2016), 10.0.17763.9376 (Windows 10 1809 / Server 2019), 10.0.19044.7807 (Windows 10 21H2/22H2), 10.0.20348.5761 (Server 2022), 10.0.22631.7652 (Windows 11 23H2), 10.0.26100.9711 and 10.0.26100.33650 (Windows 11 24H2 / Server 2025), 10.0.26200.9711 (Windows 11 25H2), 10.0.26300.9711 (Windows 11 26H2), 10.0.28000.3231 (Windows 11 26H1), and 6.2.9200.26434 / 6.3.9600.23470 (Server 2012 / 2012 R2); for out-of-support platforms the same builds are the only supported path and migration should be prioritised. Since exploitation requires an existing low-privileged local session, the most effective compensating controls are reducing the number of interactive and service accounts that can log on locally to servers and workstations, enforcing least privilege and just-in-time administration, and restricting lateral movement so that an attacker cannot obtain the foothold the CWE-415 double free requires. Where wired 802.1X is not deployed, disabling the Wired AutoConfig service (dot3svc) or setting it to Manual removes the attack surface entirely, with the trade-off that any wired 802.1X/NAC enforcement may stop working and policy-managed Ethernet authentication profiles will fail; if 802.1X is in use on specific interfaces, scope the change to non-802.1X endpoints rather than disabling globally. Because SSVC marks exploitation as 'none' and automatable as 'no', patch deployment can follow standard monthly cadence rather than emergency change control, but monitor for crash or exception telemetry from dot3svc, which is a plausible precursor to exploitation attempts, and note that no public exploit code has been identified at time of analysis.

Affected VersionsENISA

Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9376
Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9376
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7807
Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 <6.3.9600.23470
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9711
Windows Server 2022 10.0.20348.0 <10.0.20348.5761
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7652
Windows Server 2012 R2 6.3.9600.0 <6.3.9600.23470
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9612
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9612
Windows Server 2019 10.0.17763.0 <10.0.17763.9376
Windows 11 Version 26H2 10.0.26300.0 <10.0.26300.9711
Windows Server 2016 10.0.14393.0 <10.0.14393.9612
Windows Server 2012 6.2.9200.0 <6.2.9200.26434
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.3231
Windows 10 Version 22H2 10.0.19045.0 <10.0.19044.7807
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33650
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9711
Windows Server 2012 (Server Core installation) 6.2.9200.0 <6.2.9200.26434
Windows Server 2025 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_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 Wired AutoConfig service (dot3svc) is the Windows component that implements IEEE 802.1X authentication and EAPOL handling for wired Ethernet interfaces, and it runs in a privileged security context. CVE-2026-85829 is a double-free (CWE-415) in that service, meaning the same heap allocation is released twice, which typically corrupts heap metadata and can be shaped into controlled memory reuse and, ultimately, arbitrary code execution in the service's privilege context. Successful abuse therefore crosses a privilege boundary from a low-privileged local user to SYSTEM. The CVSS vector AV:L/PR:L/UI:N confirms the attacker must already be executing locally with some valid credentials or session, that no victim interaction is required, and that the attack complexity is low. All affected builds are the NT 6.2, 6.3 and 10.0 families listed in the EUVD data (e.g., 10.0.17763, 10.0.19044/19045, 10.0.22631, 10.0.26100, 10.0.26200, 10.0.26300, 10.0.28000), which indicates the defect is present in a broadly shared dot3svc code path rather than a single edition-specific branch. Note that the source feed carries an 'Information Disclosure' tag while the authoritative CVSS metrics and the SSVC 'total' technical impact rating indicate full high confidentiality, integrity and availability impact once escalation succeeds; the vector and the independent assessment should be treated as controlling.

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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 post-authentication escalation (AV:L, PR:L) with no user interaction; a double free driven to SYSTEM code execution gives full C/I/A, scope unchanged within the OS.

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 - 19:21 cve.org
HIGH 7.8

DescriptionCVE.org

Double free in Windows Wired AutoConfig Service allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

A high-severity flaw in the Microsoft Windows Wired AutoConfig Service affects every supported Windows 10, Windows 11, and Windows Server release from 2012 through 2025, letting someone who already holds a low-privileged account on a machine take full system-level control of that host. Because the affected component ships by default across the entire Windows estate, including servers, any single compromised user credential, contractor laptop, or help-desk account can be converted into machine-wide control, amplifying the damage of every other security incident. There is no evidence of active exploitation or public exploit code at this time, so leadership should treat this as a post-compromise escalation risk to close on a planned cycle rather than a remote, wormable emergency.

Business Impact: Medium
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 77% exploitable
Prevalence
Ubiquitous
Core Windows service shipped across all supported client and server builds
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
Medium
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
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