Microsoft Windows LSASS: Elevation of privilege via heap-based buffer overflow
Summary
A heap-based buffer overflow in the Windows Local Security Authority Subsystem Service (LSASS) allows an authorized local attacker to elevate privileges. The attack vector is local and requires low privileges and no user interaction. A successful attacker could take full control of the affected system and potentially access stored credentials, so affected Windows clients and servers should be patched promptly.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9688)
- Windows 10 Version 1809 (builds before 10.0.17763.9487)
- Windows 10 Version 21H2 (builds before 10.0.19044.7846)
- Windows 10 Version 22H2 (builds before 10.0.19045.7846, not verified against the vendor record)
- Windows 11 Version 23H2 (builds before 10.0.22631.7711)
- Windows 11 Version 24H2 (builds before 10.0.26100.9974)
- Windows 11 Version 25H2 (builds before 10.0.26200.9974)
- Windows 11 Version 26H1 (builds before 10.0.28000.3501)
- Windows 11 Version 26H2 (builds before 10.0.26300.9974)
- Windows Server 2016 incl. Server Core (builds before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (builds before 10.0.17763.9487)
- Windows Server 2022 (builds before 10.0.20348.5870)
Fixed in
Install the current cumulative update for each affected build. According to the CNA record, the fixed builds are the versions listed above (the first build not affected). Verify the exact fixed builds on the MSRC advisory before rollout.
Workaround
Unknown. No workaround or mitigation guidance was found in the sources.
Exploitation
- Not known to be exploited in the wild.
- No public proof-of-concept code known.
- CISA SSVC: Exploitation none, automatable no, technical impact total.
Our recommendation
- Inventory all Windows 10, 11 and Server systems and compare their builds with the fixed versions.
- Install the current security update, prioritising servers and privileged administrator workstations.
- Check the support status of Windows 10 1607 and 1809 and plan upgrades where needed.
- Limit local logon and restrict untrusted local programs, and monitor for signs of privilege escalation.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Local Security Authority Subsystem Service (LSASS)
- 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 Response Center advisory CVE-2026-88227 msrc.microsoft.com
- CVE.org CVE record CVE-2026-88227 www.cve.org
- VulDB entry CVE-2026-88227 vuldb.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, 03:20.
Original description (NVD)
Heap-based buffer overflow in Windows Local Security Authority Subsystem Service (LSASS) 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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