Microsoft Windows up to Server 2022 ALPC heap-based overflow

Summaryinfo

A vulnerability was found in Microsoft Windows up to Server 2022. It has been rated as very critical. This affects an unknown function of the component ALPC. Performing a manipulation results in heap-based overflow. This vulnerability is identified as CVE-2026-85880. The attack is only possible with local access. Additionally, an exploit exists. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Windows up to Server 2022. It has been classified as very critical. This affects an unknown function of the component ALPC. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.

The advisory is shared at msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2026-85880 since 09/04/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are unknown but an exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/09/2026).

It is declared as attacked. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 09/08/2026 with a due date of 09/22/2026:

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 BO

Applying a patch is able to eliminate this problem.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• 10 21H2
• 10 22H2
• 10 1607
• 10 1809
• Server 2012
• Server 2012 R2
• Server 2016
• Server 2019
• Server 2022

License

• commercial

Website

• Vendor: https://www.microsoft.com/
• Product: https://www.microsoft.com/en-us/windows

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