Actively exploited · Published Sep 8, 2026 · Assigned by microsoft
CVE-2026-85880Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability
High 7.8 Exploited
In plain English
A high-severity heap buffer overflow in Windows 10 Version 1607 from Microsoft. Attackers are actively exploiting it in the wild (listed by CISA on September 8, 2026). The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA guidance
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Federal agencies must remediate by Sep 22, 2026.
Official description
Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 – before 10.0.14393.9512 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 – before 10.0.17763.9245 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 – before 10.0.19044.7725 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 – before 10.0.19045.7725 |
| Microsoft | Windows Server 2012 | 6.2.9200.0 – before 6.2.9200.26349 |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 – before 6.2.9200.26349 |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 – before 6.3.9600.23398 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 – before 6.3.9600.23398 |
| Microsoft | Windows Server 2016 | 10.0.14393.0 – before 10.0.14393.9512 |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 – before 10.0.14393.9512 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 – before 10.0.17763.9245 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 – before 10.0.17763.9245 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – before 10.0.20348.5622 |
Weakness: CWE-122, CWE-908 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
References
- Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880 government-resource