CVE intelligence

CVE-2026-83903

Vulnerability intelligence

Published Oct 13, 2026Sources checked Oct 21, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-83903 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 13, 2026

Vendor remediation details

Install KB5127648. Install KB5126646.

Vendor-listed releases

10.0.26300.9711
10.0.26100.33650
10.0.26200.9711
10.0.26100.9711

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-83903?

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

Source: NVD