Heap-Based Buffer Overflow in Windows NTFS Enables Local Code Execution

Publication date: 2026-01-13

Last updated on: 2026-01-13

Assigner: Microsoft Corporation

Description

Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-01-13

Last Modified

2026-01-13

Generated

2026-07-06

AI Q&A

2026-01-14

EPSS Evaluated

2026-07-05

NVD

CVE-2026-20840

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_ntfs	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
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().

Attack-Flow Graph

Executive Summary

This vulnerability is a heap-based buffer overflow in Windows NTFS that allows an authorized attacker to execute code locally on the affected system. [1]

Impact Analysis

An attacker with local authorization can exploit this vulnerability to execute arbitrary code, potentially leading to full system compromise including high impact on confidentiality, integrity, and availability. [1]

Hi! I’m here to help you understand CVE-2026-20840. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70