Microsoft Windows: Information disclosure in System Events Broker
Summary
A use-after-free flaw in the Windows System Events Broker component allows information disclosure. An attacker with a valid, low-privileged local account can infer limited memory contents of a privileged process by observing comparison results. Microsoft states that no unrestricted read access to process memory is provided, and no code execution or privilege escalation is claimed. The CVSS base score is 5.5 (medium).
Affected
- Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9688)
- Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9487)
- Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7846)
- Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7846)
- Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7711)
- Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9974)
- Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9974)
- Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3501)
- Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9974)
- Windows Server 2016 incl. Server Core (10.0.14393.0 to before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (10.0.17763.0 to before 10.0.17763.9487)
- Windows Server 2022 (10.0.20348.0 to before 10.0.20348.5870)
Fixed in
- Windows 10 1607 / Server 2016: 10.0.14393.9688
- Windows 10 1809 / Server 2019: 10.0.17763.9487
- Windows 10 21H2: 10.0.19044.7846
- Windows 10 22H2: 10.0.19045.7846
- Windows 11 23H2: 10.0.22631.7711
- Windows 11 24H2: 10.0.26100.9974
- Windows 11 25H2: 10.0.26200.9974
- Windows 11 26H1: 10.0.28000.3501
- Windows 11 26H2: 10.0.26300.9974
- Windows Server 2022: 10.0.20348.5870
- Windows Server 2025: Unknown, verify on the MSRC page
Fix is provided by the November 2026 cumulative update. Verify the build numbers and KB numbers per product on the MSRC page before deployment.
Workaround
Unknown.
Exploitation
- Microsoft lists the flaw as not exploited.
- No public proof of concept found.
- Not known to be in the CISA KEV catalogue (not directly verified).
- CISA SSVC: exploitation none, not automatable, partial technical impact.
Our recommendation
- Apply the November 2026 cumulative update to all affected Windows builds through the normal monthly patch cycle.
- Prioritise terminal servers, Remote Desktop hosts and shared multi-user systems, where many users have local logons.
- Check which systems have local user accounts beyond administrators and restrict unnecessary logons.
- Single-user workstations carry lower practical risk but should still be patched.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows System Events Broker
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131085, KB5131080, KB5131077, KB5132061, KB5132043, KB5131090
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-105530 msrc.microsoft.com
- CVE Record CVE-2026-105530 (CVE.org) www.cve.org
- Strix: CVE-2026-105530 (third-party aggregator) www.strix.ai
- Senserva KB5131090 (third-party, Server 2022) senserva.com
- Senserva KB5131080 (third-party, Server 2025) senserva.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, 17:03.
Original description (NVD)
Use after free in Windows System Events Broker 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.
Affected? We can help.
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