Windows Storage: Heap-based buffer overflow enables local privilege escalation
Summary
A heap-based buffer overflow in the Windows Storage component allows an authorized local attacker to elevate privileges. Successful exploitation could lead to high impact on confidentiality, integrity and availability of the affected system. The attacker needs a low-privilege local account and the attack complexity is high, so the flaw is not directly reachable from the internet.
Affected
- Windows 11 version 23H2: builds 10.0.22631.0 to below 10.0.22631.7652
- Windows 11 version 24H2: builds 10.0.26100.0 to below 10.0.26100.9711
- Windows 11 version 25H2: builds 10.0.26200.0 to below 10.0.26200.9711
- Windows 11 version 26H1: builds 10.0.28000.0 to below 10.0.28000.3231
- Windows 11 version 26H2: builds 10.0.26300.0 to below 10.0.26300.9711
- Windows Server 2022: builds 10.0.20348.0 to below 10.0.20348.5761
- Windows Server 2025 (including Server Core): builds 10.0.26100.0 to below 10.0.26100.33650
- Note: the NVD CPE list names only Windows 11 23H2; the CNA record lists the products above.
Fixed in
- Install the October 2026 security updates from Microsoft for the affected versions.
- Fixed builds according to the CNA record: 22631.7652 (23H2), 26100.9711 (24H2), 26200.9711 (25H2), 28000.3231 (26H1), 26300.9711 (26H2), 20348.5761 (Server 2022), 26100.33650 (Server 2025).
- Verify the fixed builds and KB numbers on the Microsoft Security Update Guide.
Workaround
Unknown beyond patching. No workaround guidance was found for this CVE.
Exploitation
- CISA SSVC: exploitation none, not automatable, technical impact total.
- No public proof of concept was found in the research; this does not prove that none exists.
- Listing on the CISA KEV catalogue could not be confirmed.
- EPSS score 0.00252 (very low).
Our recommendation
- Apply the October 2026 cumulative updates in the normal patch cycle; prioritize terminal servers, file servers and systems with many local users.
- Verify the fixed builds on the Microsoft advisory before rollout.
- Restrict local logon rights and review local accounts on shared machines.
- Monitor for unexpected privilege changes and new local administrator accounts.
- Recheck the CISA KEV catalogue and public exploit sources at the next review.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-102191 msrc.microsoft.com
- Strix AI: CVE-2026-102191 (CNA data mirror) www.strix.ai
- NVD record via Vulners: CVE-2026-102191 vulners.com
- CVEfeed: CVE-2026-102191 cvefeed.io
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 4 Nov 2026, 09:57.
Original description (NVD)
Heap-based buffer overflow in Windows Storage allows an authorized attacker to elevate privileges locally.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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