CVE-2026-88121
Undergoing Analysis Undergoing Analysis - In Progress

Use After Free in Windows BITS Allows Remote Code Execution

Vulnerability report for CVE-2026-88121, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Use after free in Windows Background Intelligent Transfer Service (BITS) allows an unauthorized attacker to execute code over a network.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-10-13
Last Modified
2026-10-16
Generated
2026-10-19
AI Q&A
2026-10-14
EPSS Evaluated
2026-10-18
NVD
EUVD

Affected Vendors & Products

Showing 21 associated CPEs
Vendor Product Version / Range
Microsoft Windows 10 Version 1607 10.0.14393.0
Microsoft Windows 10 Version 1809 10.0.17763.0
Microsoft Windows 10 Version 21H2 10.0.19044.0
Microsoft Windows 10 Version 22H2 10.0.19045.0
Microsoft Windows 11 version 23H2 10.0.22631.0
Microsoft Windows 11 Version 23H2 10.0.22631.0
Microsoft Windows 11 Version 24H2 10.0.26100.0
Microsoft Windows 11 Version 25H2 10.0.26200.0
Microsoft Windows 11 version 26H1 10.0.28000.0
Microsoft Windows 11 Version 26H2 10.0.26300.0
Microsoft Windows Server 2012 6.2.9200.0
Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.0
Microsoft Windows Server 2012 R2 6.3.9600.0
Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.0
Microsoft Windows Server 2016 10.0.14393.0
Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.0
Microsoft Windows Server 2019 10.0.17763.0
Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.0
Microsoft Windows Server 2022 10.0.20348.0
Microsoft Windows Server 2025 10.0.26100.0
Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.0

Helpful Resources

Exploitability

CWE
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KEV
KEV Icon
CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

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Executive Summary

This vulnerability is a use after free issue in Windows Background Intelligent Transfer Service (BITS). It allows an unauthorized attacker to execute arbitrary code over a network by exploiting a memory corruption flaw.

Detection Guidance

This vulnerability involves a use-after-free flaw in Windows BITS. Detection typically requires monitoring for unusual network activity or crashes in BITS-related processes. Check Windows Event Logs for BITS errors or application crashes. Use commands like 'sc query bits' to verify BITS service status and 'Get-WinEvent -LogName Application -FilterXPath "*/System[Provider[@Name='Application Error']]"' to inspect crashes.

Impact Analysis

An attacker could exploit this to run malicious code on your system, potentially leading to data theft, system compromise, or further network attacks. It requires network access but no user interaction.

Compliance Impact

This vulnerability allows remote code execution via a use-after-free flaw in Windows BITS. Such flaws can lead to unauthorized access, data breaches, or system compromise, which may violate GDPR's integrity and confidentiality requirements or HIPAA's safeguards for protected health information.

Mitigation Strategies

Apply the latest Windows security updates immediately. Disable the BITS service if not required using 'sc stop bits' and 'sc config bits start= disabled'. Restrict network access to BITS ports (TCP 443) via firewall rules. Monitor for suspicious activity and isolate affected systems if exploitation is suspected.

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