CVE-2026-85880: Microsoft Windows Heap-Based Buffer Overflow Vulnerability

Microsoft · Windows

Listed by CISA as exploited in the wild since 8 Sep 2026. Below: exploitation status, EPSS and every published CVSS, each with its source, then affected versions and references.

Build snapshot collected 3 Oct 2026, 08:57 UTC · KEV catalog 2026.10.02 · EPSS of 2 Oct 2026 · not a live feed: collected once, at build time

Description

as written by CISA (KEV catalog)

Microsoft Windows Advanced Local Procedure Call contains a heap-based buffer overflow vulnerability that allows an attacker to elevate privileges locally.

Required action

CISA KEV

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.

Affected products and versions

CVE record · microsoft

Microsoft · Windows 10 Version 1607
- affected: from 10.0.14393.0 before 10.0.14393.9512
Microsoft · Windows 10 Version 1809
- affected: from 10.0.17763.0 before 10.0.17763.9245
Microsoft · Windows 10 Version 21H2
- affected: from 10.0.19044.0 before 10.0.19044.7725
Microsoft · Windows 10 Version 22H2
- affected: from 10.0.19045.0 before 10.0.19045.7725
Microsoft · Windows Server 2012
- affected: from 6.2.9200.0 before 6.2.9200.26349
Microsoft · Windows Server 2012 (Server Core installation)
- affected: from 6.2.9200.0 before 6.2.9200.26349
Microsoft · Windows Server 2012 R2
- affected: from 6.3.9600.0 before 6.3.9600.23398
Microsoft · Windows Server 2012 R2 (Server Core installation)
- affected: from 6.3.9600.0 before 6.3.9600.23398
Microsoft · Windows Server 2016
- affected: from 10.0.14393.0 before 10.0.14393.9512
Microsoft · Windows Server 2016 (Server Core installation)
- affected: from 10.0.14393.0 before 10.0.14393.9512
Microsoft · Windows Server 2019
- affected: from 10.0.17763.0 before 10.0.17763.9245
Microsoft · Windows Server 2019 (Server Core installation)
- affected: from 10.0.17763.0 before 10.0.17763.9245
Microsoft · Windows Server 2022
- affected: from 10.0.20348.0 before 10.0.20348.5622

Status words (affected, unaffected, unknown) and version bounds are copied from the record. An upper bound such as “before 7.1.0” usually marks the first fixed version; confirm in the vendor advisory before planning an upgrade.

References

CISA KEV notes and CVE record

EPSS over the last 30 days

Other Microsoft entries in KEV

Added in the same week (see the week)

Questions about CVE-2026-85880

Is CVE-2026-85880 being exploited?

Yes, according to CISA. CVE-2026-85880 was added to the Known Exploited Vulnerabilities catalog on 8 Sep 2026, which CISA does only with reliable evidence of exploitation in the wild. The catalog field for ransomware campaign use says "Unknown".

What is the deadline to remediate CVE-2026-85880?

CISA set 22 Sep 2026 as the due date for US Federal Civilian Executive Branch agencies. The date is binding only for those agencies; other organisations can read it as a measure of urgency.

What is the EPSS score of CVE-2026-85880?

3.62%, in the 89th percentile, in the FIRST EPSS model of 2 Oct 2026. It estimates the probability of exploitation activity in the following 30 days. For a CVE already in KEV the score is secondary: exploitation has been observed.

How severe is CVE-2026-85880?

microsoft.com rates it 7.8 HIGH (CVSS 3.1). These are the published assessments as of 3 Oct 2026; this site does not rescore.

Which product does CVE-2026-85880 affect?

Microsoft Windows, as named in the CISA catalog. The affected versions listed in the CVE record are on this page; the vendor advisory in the references is the authority on fixed versions.