Microsoft Windows SMB Client: Local privilege escalation via pointer dereference
Summary
The Windows SMB Client contains an untrusted pointer dereference (CWE-822) that allows an authorized local attacker to elevate privileges. An attacker first needs a foothold on the system, for example through a phished or stolen standard user account or code already running as a standard user. The flaw is not remotely exploitable; the CVSS 7.0 score reflects the high impact on confidentiality, integrity and availability.
Affected
- Windows 10 Version 1607 (before 10.0.14393.9688)
- Windows 10 Version 1809 (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 2016 incl. Server Core (before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (before 10.0.17763.9487)
- Windows Server 2022 (before 10.0.20348.5870)
Fixed in
- Fixed in the November 2026 security updates for the affected branches (first build not affected, see Affected).
- KB number: Unknown.
Workaround
Unknown.
- No workaround identified; apply the update.
Exploitation
- Exploited in the wild: Not known.
- Exploit maturity per CNA record: Unproven (E:U).
- Public proof of concept: None found.
- CISA SSVC: Exploitation none, automatable no, technical impact total.
Our recommendation
- Patch affected Windows 10, Windows 11 and Windows Server systems with the November 2026 cumulative updates, starting with file servers and admin workstations.
- Confirm build numbers in the MSRC entry and check the support status of older branches such as 1607 and 1809.
- Keep SMB (TCP 445) closed at the internet edge.
- Monitor workstations and file servers for unusual privilege changes.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows SMB Client
- 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-2026-119870 msrc.microsoft.com
- CVE.org CNA record CVE-2026-119870 www.cve.org
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.com
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, 08:34.
Original description (NVD)
Untrusted pointer dereference in Windows SMB Client 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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