CVE-2026-62739

Analyzed Analyzed - Analysis Complete

Heap-based Buffer Overflow in Windows HTTP.sys

Publication date: 2026-08-11

Last updated on: 2026-08-16

Assigner: Microsoft Corporation

Description

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

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-11

Last Modified

2026-08-16

Generated

2026-09-01

AI Q&A

2026-08-12

EPSS Evaluated

2026-08-30

NVD

CVE-2026-62739

EUVD

EUVD-2026-56368

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_10_1809	to 10.0.17763.9115 (exc)
microsoft	windows_10_1809	to 10.0.17763.9115 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7663 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7663 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7663 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7663 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7663 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7663 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7517 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7517 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9106 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9106 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9106 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9106 (exc)
microsoft	windows_server_2019	to 10.0.17763.9115 (exc)
microsoft	windows_server_2022	to 10.0.20348.5440 (exc)
microsoft	windows_server_2025	to 10.0.26100.33222 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-197	Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.
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 is a heap-based buffer overflow vulnerability in Windows HTTP.sys. It allows an authorized attacker with local access to elevate their privileges on the system by exploiting a flaw in memory handling.

Detection Guidance

Detection requires checking for Windows systems with HTTP.sys component. Use PowerShell: Get-WindowsPackage -Name 'Microsoft-Windows-HttpProxy' to verify installation. Check for recent updates via Get-HotFix or system update history. Monitor for unusual privilege escalation events in Windows Event Logs under Security and System categories.

Impact Analysis

An attacker could gain higher privileges on your system, potentially allowing them to install programs, view or delete data, or create new accounts with full user rights.

Compliance Impact

This vulnerability allows local privilege escalation via a heap-based buffer overflow in Windows HTTP.sys. While it does not directly impact data confidentiality or integrity, unauthorized privilege escalation could lead to broader system compromise, potentially affecting compliance controls that rely on proper access restrictions.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the heap-based buffer overflow in HTTP.sys. Monitor Microsoft's update guide for the specific patch release.

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