IT SBIT Services
Schneeberger
DEEN
CVE tracker

Windows: Out-of-bounds read in DWM Core Library allows local privilege escalation

CVE-2026-88188High 7.8

← All vulnerabilities

Summary

Windows contains an out-of-bounds read (CWE-125) in the Desktop Window Manager (DWM) Core Library. An attacker with local, low-privilege access to an affected system can exploit it to elevate privileges, which can lead to full control of the machine (CVSS 7.8). The attacker needs an existing foothold on the system, and the flaw is not directly reachable from the network.

Affected

  • Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9612)
  • Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9376)
  • Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7807)
  • Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7807)
  • Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7652)
  • Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9711)
  • Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9711)
  • Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9711)
  • Windows Server 2016, including Server Core (10.0.14393.0 to before 10.0.14393.9612)
  • Windows Server 2019, including Server Core (10.0.17763.0 to before 10.0.17763.9376)
  • Windows Server 2022 (10.0.20348.0 to before 10.0.20348.5761)
  • Windows Server 2025 (10.0.26100.0 to before 10.0.26100.33650)

Fixed in

  • Security update released October 13, 2026, per the Microsoft Security Update Guide.
  • Windows Server 2025: KB5126646 (October 2026 update, per a third-party record; verify).
  • Windows 10 Version 1607: KB number and fixed build unknown; verify on the MSRC page.

Workaround

  • Unknown. No workaround was found in the sources reviewed. Install the update.

Exploitation

  • Exploited in the wild: no evidence found; no CISA KEV listing found in the searches performed.
  • CISA SSVC: exploitation none, automatable no, technical impact total.
  • Microsoft rates exploit code maturity as unproven (E:U).
  • Public proof of concept: none found.
  • EPSS: 0.00318.

Our recommendation

  • Install the October 2026 Windows security update on all affected systems, starting with endpoints and servers where untrusted users or code could run.
  • Confirm the exact fixed builds and KB numbers on the MSRC page before deploying.
  • Replace or upgrade any Windows 10 Version 1607 systems and check Microsoft's lifecycle date for this version.
  • Monitor for unexpected privilege changes and new local administrator accounts.

Information from Microsoft (Patch Tuesday October 2026)

Severity (Microsoft)
Important
Impact
Elevation of privilege – Windows DWM Core Library
Status on Patch Tuesday
Neither exploited nor publicly disclosed
Exploitability assessment
Exploitation less likely
Product family
Windows, Windows ESU (Extended Security Updates)
Updates (KB)
KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653

Entry in the Microsoft Security Update Guide

Public exploits

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 2 Nov 2026, 01:11.

Original description (NVD)

Out-of-bounds read in Windows DWM Core Library allows an authorized attacker to elevate privileges locally.

NVD references (1)

Sources

The tracker combines official, freely usable data sources – updated continuously:

This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.

Affected? We can help.

We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.

Get in touchRSS feed