CVE-2026-26169 Overview
CVE-2026-26169 is a buffer over-read vulnerability in Windows Kernel Memory that allows an authorized local attacker to disclose sensitive information. The flaw is classified under [CWE-126: Buffer Over-read] and affects a broad range of Microsoft Windows client and server editions. An attacker with low-privilege local access can read memory beyond an intended buffer boundary, exposing kernel data that should remain isolated from user-mode processes. Microsoft published the advisory on April 14, 2026.
Critical Impact
Successful exploitation discloses Windows kernel memory contents to an authenticated local attacker, potentially leaking pointers, secrets, or data usable to bypass kernel address space layout randomization (KASLR) and chain further attacks.
Affected Products
- Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 23H2, 24H2, 25H2, 26H1)
- Microsoft Windows Server 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2026-04-14 - CVE-2026-26169 published to NVD
- 2026-04-14 - Microsoft releases security advisory and patch
- 2026-04-24 - Last updated in NVD database
Technical Details for CVE-2026-26169
Vulnerability Analysis
The vulnerability is a buffer over-read [CWE-126] in Windows Kernel Memory. The kernel reads past the end of an allocated buffer, returning adjacent memory contents to a caller that should not have access to that data. Because the over-read occurs in kernel space, the disclosed bytes can include sensitive structures, pointers, or cryptographic material.
The attack vector is local, requires low privileges, and needs no user interaction. Exploitation does not enable code execution or modification of system state directly, but the leaked information is high-impact. Disclosed kernel pointers commonly serve as a precursor to defeating KASLR, allowing attackers to reliably target follow-on kernel memory corruption vulnerabilities.
Root Cause
Buffer over-read conditions in kernel code typically arise from missing or incorrect length validation when copying data between kernel and user buffers, or when iterating over structures whose declared size does not match the underlying allocation. The kernel returns memory contents beyond the legitimate buffer boundary to the requesting context. Microsoft has not published low-level technical details about the specific subsystem affected.
Attack Vector
An authenticated local user invokes the affected kernel interface from a standard user context. The vulnerable code path reads beyond the intended buffer and returns the resulting bytes to the user-mode caller. The attacker captures these bytes and parses them for kernel addresses, handles, or other sensitive data. No remote network access and no administrative rights are required.
No public proof-of-concept code or in-the-wild exploitation has been reported. The EPSS probability is 0.073% as of May 16, 2026.
Detection Methods for CVE-2026-26169
Indicators of Compromise
- No publicly documented file hashes, network indicators, or post-exploitation artifacts are associated with this vulnerability.
- Unusual or repeated invocation of kernel system calls from low-privilege processes, particularly calls that return variable-length buffers, may indicate probing activity.
Detection Strategies
- Monitor process behavior for low-privilege user-mode processes performing high-frequency syscalls or device I/O control (DeviceIoControl) operations targeting kernel components.
- Correlate local logon events with subsequent execution of unsigned or unusual binaries that interact with kernel interfaces.
- Hunt for tooling commonly used to enumerate kernel structures, such as utilities that call NtQuerySystemInformation from non-administrative contexts.
Monitoring Recommendations
- Enable Windows Defender Application Control or AppLocker logging to track unsigned binaries executing on endpoints.
- Ingest Sysmon process creation and image load events into a centralized log store for behavioral analytics.
- Track patch compliance across all affected Windows builds and alert on systems missing the April 2026 cumulative update.
How to Mitigate CVE-2026-26169
Immediate Actions Required
- Apply the April 2026 Microsoft security update to all affected Windows 10, Windows 11, and Windows Server systems.
- Inventory endpoints and servers against the affected version list and prioritize patching for multi-user systems where local accounts exist.
- Restrict local interactive logon rights to reduce the pool of accounts that can reach the vulnerable code path.
Patch Information
Microsoft has released cumulative security updates that remediate CVE-2026-26169 across all supported Windows client and server versions. Refer to the Microsoft Security Update for CVE-2026-26169 for the specific KB articles and build numbers applicable to each affected SKU.
Workarounds
- Microsoft has not published an official workaround. Patching is the only supported remediation.
- As a compensating control, enforce least-privilege policies and remove unnecessary local accounts to reduce exposure until the patch is deployed.
- Apply credential hardening and limit Remote Desktop access to trusted administrators, reducing the population of authenticated users on a host.
# Verify patch installation status on Windows endpoints
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 10
# Query current OS build to confirm it includes the April 2026 update
[System.Environment]::OSVersion.Version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
