CVE-2026-69862: Windows WWAN Service Information Disclosure

CVE-2026-69862 Overview

CVE-2026-69862 is an out-of-bounds read vulnerability [CWE-125] in the Windows Wireless Wide Area Network (WWAN) Service. An authorized local attacker can exploit the flaw to disclose sensitive information from process memory. The issue requires local access and low-level privileges, and no user interaction is needed to trigger it. Microsoft has published guidance in the Microsoft Security Response Center (MSRC) update guide.

Critical Impact
Successful exploitation allows a local authenticated attacker to read memory outside the intended buffer boundary in the Windows WWAN Service, exposing potentially sensitive data handled by the service.

Affected Products

Microsoft Windows (Wireless Wide Area Network Service component)
See Microsoft Security Update CVE-2026-69862 for the authoritative list of affected builds
Systems using cellular or WWAN connectivity features are directly exposed to the vulnerable service

Discovery Timeline

2026-09-08 - CVE-2026-69862 published to NVD
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-69862

Vulnerability Analysis

The Windows Wireless Wide Area Network Service (wwansvc) manages cellular and mobile broadband connectivity on Windows systems. The vulnerability stems from an out-of-bounds read [CWE-125] in this service. The service reads beyond the boundaries of an allocated buffer while processing input, returning adjacent memory contents to the caller.

Exploitation requires local access with valid credentials on the target system. The attacker interacts with the WWAN service through its exposed interfaces to trigger the boundary violation. Successful exploitation returns memory contents that the caller was not authorized to access. The impact is limited to confidentiality; the flaw does not permit modification of data or disruption of service.

The Exploit Prediction Scoring System (EPSS) rates the probability of exploitation activity at 0.469%. No public proof-of-concept code has been observed at time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Root Cause

The root cause is missing or insufficient bounds checking on a read operation within the WWAN service. When the service processes a request, it fails to validate the size or offset of the target buffer before dereferencing memory. This results in the service reading past the intended buffer end and returning uninitialized or unrelated memory content to the caller.

Attack Vector

The attack vector is local. An authenticated attacker on the target system sends crafted input to the WWAN service via its inter-process communication interface. The malformed request triggers the out-of-bounds read within the service process. The attacker receives leaked memory contents in the response, which may include credentials, cryptographic material, or other data handled by the service.

Because exploitation requires only low privileges and no user interaction, standard user accounts on affected systems can perform the attack. See the Microsoft Security Update CVE-2026-69862 advisory for further technical details.

Detection Methods for CVE-2026-69862

Indicators of Compromise

Unexpected crashes or exceptions in the wwansvc service process, which may indicate probing attempts
Unusual local process activity interacting with WWAN service RPC endpoints from non-administrative user contexts
Anomalous handles opened against the Wireless WAN service by processes that do not normally interact with cellular connectivity

Detection Strategies

Monitor Windows Event Logs for wwansvc service faults, restarts, or Windows Error Reporting (WER) entries tied to the service
Deploy endpoint detection rules that flag low-privilege processes issuing repeated or malformed RPC calls to the WWAN service
Correlate local process telemetry with RPC interface access patterns to surface attempts to enumerate or fuzz the vulnerable interface

Monitoring Recommendations

Collect process creation, module load, and RPC call telemetry from Windows endpoints with cellular capabilities
Baseline normal interactions with the WWAN service on affected hosts and alert on deviations from that baseline
Retain memory-access and service-crash telemetry long enough to support retrospective hunts once additional indicators become available

How to Mitigate CVE-2026-69862

Immediate Actions Required

Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-69862 to all affected Windows systems
Prioritize patching on multi-user systems and endpoints where local accounts are shared or exposed to less-trusted users
Audit accounts with local logon rights on affected hosts and remove unnecessary standing access

Patch Information

Microsoft has issued a security update through the MSRC update guide for CVE-2026-69862. Administrators should consult the Microsoft Security Update CVE-2026-69862 page to identify the specific Knowledge Base (KB) update for each affected Windows build and deploy the update through Windows Update, WSUS, or the enterprise patch management tool of record.

Workarounds

Disable the Windows Wireless WAN Service (wwansvc) on systems that do not require cellular or mobile broadband connectivity
Restrict local logon rights to reduce the pool of users who can trigger the vulnerable code path
Apply application allowlisting to limit which processes can invoke the WWAN service interfaces

bash

# Configuration example: disable the WWAN service on systems that do not need cellular connectivity
sc.exe config wwansvc start= disabled
sc.exe stop wwansvc