Windows Shell: Buffer over-read causes local information disclosure
Summary
Windows Shell, the core user interface component of Windows, contains a buffer over-read (CWE-126) that can disclose information. A local attacker with a valid account and low privileges can read memory they should not see, but user interaction is required. Only confidentiality is affected; integrity and availability are not.
Affected
- Windows 10 Version 1607 and Windows Server 2016 (incl. Server Core): before 10.0.14393.9688
- Windows 10 Version 1809 and Windows Server 2019 (incl. Server Core): before 10.0.17763.9487
- Windows 10 Version 21H2: before 10.0.19044.7846
- Windows 10 Version 22H2: before 10.0.19045.7846
- Windows 11 Version 23H2: before 10.0.22631.7711
- Windows 11 Version 24H2: before 10.0.26100.9974
- Windows 11 Version 25H2: before 10.0.26200.9974
- Windows 11 Version 26H1: before 10.0.28000.3501
- Windows 11 Version 26H2: before 10.0.26300.9974
- Windows Server 2022: before 10.0.20348.5870
Build values are taken from the CVE record. The record was incomplete at research time, so verify them against the MSRC table.
Fixed in
- November 2026 cumulative update (released 10 Nov 2026) for each affected branch.
- Confirm that the build number is at or above the values listed under affected.
Workaround
Unknown. No vendor workaround was found in the sources reviewed. Check the full MSRC page before relying on any mitigation.
Exploitation
- Microsoft reports it as not publicly disclosed and not exploited (Exploit Code Maturity: Unproven).
- CISA SSVC: exploitation none, automatable no.
- Not listed in CISA KEV (according to Strix). No public proof of concept found.
- NVD analysis was still pending at the time of research.
Our recommendation
- Install the November 2026 cumulative update on all affected Windows clients and servers.
- Prioritise Remote Desktop hosts, terminal servers, shared workstations and multi-user file servers.
- Confirm the installed build number after patching.
- Check the full MSRC page for the complete build table and any mitigation.
- Monitor KEV and NVD for changes in exploitation status.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Shell
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-105506 msrc.microsoft.com
- CVE Record CVE-2026-105506 (CVE.org) www.cve.org
- Strix: CVE-2026-105506 www.strix.ai
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 11 Nov 2026, 19:15.
Original description (NVD)
Buffer over-read in Windows Shell allows an authorized attacker to disclose information 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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