Microsoft Windows Heap-Based Buffer Overflow Vulnerability
Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
What happened
Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
CISA lists it as exploited, added 08 Sep 2026.
Does it affect you
Names Microsoft Windows Server. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Apply the vendor patch named in this advisory.
msrc.microsoft.com - 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.gov
CISA’s notes for this entry:
- msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-85880
- BOD 26-04: cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- Forensics Triage Requirements: cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- nvd.nist.gov/vuln/detail/CVE-2026-85880
Affected, as published to NVD
- ms-winserver
- Microsoft Windows Server: everything below 10.0.14393.9512
The record
- NVD status
- Analyzed
- Published
- 08 Sep 2026, last modified 09 Sep 2026 (NVD)
- Severity
- CVSS 3.1 base score 7.8, High — computed here from the vector; NVD states 7.8.
- Vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness
- CWE-122 Heap-based Buffer Overflow, CWE-908 Use of Uninitialized Resource (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 08 Sep 2026; federal remediation due 22 Sep 2026. CISA entry
- Vendor
- Microsoft · Windows (CISA)
References on the NVD record
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880PatchVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880US Government Resource
Reporting that names this identifier
- CISA Adds Four Known Exploited Vulnerabilities to Catalog — CISA, 24 hr ago
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.