CVE-2026-62735

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:
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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-2026-62735

EUVD

EUVD-2026-56366

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_10_1607	to 10.0.14393.9418 (exc)
microsoft	windows_10_1607	to 10.0.14393.9418 (exc)
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_2016	to 10.0.14393.9418 (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-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().
CWE-190	The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

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.

Detection Guidance

Detection requires checking for Windows systems with HTTP.sys enabled. Use PowerShell: Get-WindowsFeature Web-HTTP-Sys or check services.msc for HTTP service. Monitor for crashes in HTTP.sys or unusual privilege escalation events in Event Viewer.

Impact Analysis

An attacker could exploit this to 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 unauthorized access to sensitive systems, potentially violating compliance requirements under GDPR, HIPAA, or other standards that mandate strict access controls and audit logging.

Mitigation Strategies

Apply the latest Windows security updates immediately. Disable HTTP.sys if not required by running: Disable-WindowsOptionalFeature -Online -FeatureName Web-HTTP-Sys. Restrict local access to authorized users only.

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