CVE-2026-85880
Microsoft Windows Heap-Based Buffer Overflow Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 22 September 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.39% probability · 33th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 8 September 2026 · due 22 September 2026
- Weakness
- CWE-122, CWE-908
- Affected
- microsoft/windows 10 1607 · microsoft/windows 10 1809 · microsoft/windows 10 21h2 · microsoft/windows 10 22h2 · microsoft/windows server 2012 · microsoft/windows server 2016 · microsoft/windows server 2019 · microsoft/windows server 2022
- Source
- secure@microsoft.com
EPSS moved from 3.6% on 24 September 2026 to 0.4% on 29 October 2026.
CISA notes
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. https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-85880 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-85880
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.