CVE-2026-69895: Windows Spaceport.sys Information Disclosure

CVE-2026-69895 Overview

CVE-2026-69895 is an out-of-bounds read vulnerability in the Windows Spaceport driver (Spaceport.sys). The flaw allows an authorized local attacker to disclose information from adjacent kernel memory. Microsoft published the advisory on September 8, 2026, and classified the issue under CWE-125 (Out-of-bounds Read).

Spaceport is the Windows Storage Spaces driver responsible for virtualizing physical storage into pools. Because the driver runs in kernel mode, memory disclosure through it can leak sensitive kernel data useful for further exploitation chains.

Critical Impact
A local, authenticated attacker can read out-of-bounds memory in Spaceport.sys to disclose information that may aid subsequent privilege escalation or bypass kernel address space layout randomization (KASLR).

Affected Products

Microsoft Windows (Spaceport driver, Spaceport.sys)
Windows Server editions shipping the Storage Spaces driver
Refer to the Microsoft CVE-2026-69895 Update Guide for the full list of affected builds

Discovery Timeline

2026-09-08 - CVE-2026-69895 published to the National Vulnerability Database (NVD)
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-69895

Vulnerability Analysis

The vulnerability resides in Spaceport.sys, the kernel-mode driver that implements Windows Storage Spaces. An out-of-bounds read occurs when the driver processes an input that causes it to read memory beyond the bounds of an allocated buffer.

Exploitation requires local access and low privileges. Attack complexity is rated high, indicating the attacker must win a race, satisfy a specific memory layout, or provide crafted input that reliably triggers the read past a buffer boundary. Successful exploitation discloses confidential kernel memory contents but does not modify data or affect availability.

Information disclosure primitives in kernel drivers are commonly chained with separate elevation-of-privilege flaws. Leaked pointers, tokens, or handle values can defeat KASLR and provide the addressing needed for a follow-on kernel write primitive.

Root Cause

The root cause is classified as [CWE-125] Out-of-bounds Read. The driver reads from a memory location computed from attacker-controlled input without validating that the offset or length remains within the allocated buffer. Microsoft has not published deeper technical details of the affected code path.

Attack Vector

The attack vector is local. An attacker must already have code execution on the target with at least standard user privileges. The attacker interacts with the Spaceport driver via IOCTL requests or storage-related APIs that reach the vulnerable code path. No user interaction is required.

Refer to the Microsoft CVE-2026-69895 Update Guide for vendor-supplied technical detail as it becomes available.

Detection Methods for CVE-2026-69895

Indicators of Compromise

No public indicators of compromise have been published for CVE-2026-69895 at this time.
Exploitation is unlikely to leave obvious file-based artifacts because the flaw yields an in-memory read only.
Monitor for unexpected local processes issuing IOCTLs to Storage Spaces devices from non-administrative contexts.

Detection Strategies

Baseline which processes legitimately interact with Spaceport.sys and alert on deviations, especially from unsigned or user-writable binaries.
Correlate suspicious local process activity with subsequent behavior consistent with kernel exploitation, such as token manipulation or new privileged process creation.
Track loading of Spaceport.sys on systems that do not use Storage Spaces, as this may indicate probing.

Monitoring Recommendations

Ingest Windows kernel and Sysmon telemetry into a centralized analytics platform to correlate low-privilege process activity with driver interaction.
Alert on repeated failed IOCTL requests to storage stack drivers from the same process, which can indicate fuzzing or exploitation attempts.
Track Microsoft patch deployment status across the fleet to identify unpatched hosts exposed to CVE-2026-69895.

How to Mitigate CVE-2026-69895

Immediate Actions Required

Apply the Microsoft security update referenced in the Microsoft CVE-2026-69895 Update Guide as soon as it is available for your Windows build.
Prioritize patching on multi-user systems, terminal servers, and virtual desktop infrastructure where untrusted local users can execute code.
Restrict local logon rights and enforce least privilege to reduce the population of accounts able to trigger the vulnerability.

Patch Information

Microsoft addresses CVE-2026-69895 through the monthly cumulative security update for affected Windows versions. Consult the Microsoft CVE-2026-69895 Update Guide for the specific knowledge base article and build numbers that resolve the issue.

Workarounds

No official vendor workaround has been published. Microsoft's guidance is to install the security update.
On systems that do not require Storage Spaces, evaluate whether the feature can be left unconfigured to reduce the attack surface exposed by Spaceport.sys.
Enforce application allowlisting so unauthorized binaries cannot execute locally to reach the vulnerable driver.

bash

# Verify installed KB updates on a Windows host to confirm the patch is applied
wmic qfe list brief /format:table

# PowerShell equivalent
Get-HotFix | Sort-Object -Property InstalledOn -Descending