CVE-2026-58637

Analyzed Analyzed - Analysis Complete

Use After Free in Windows CSC Service Elevates Privileges

Publication date: 2026-07-14

Last updated on: 2026-07-22

Assigner: Microsoft Corporation

Description

Use after free in Windows Client-Side Caching (CSC) Service allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-14

Last Modified

2026-07-22

Generated

2026-08-04

AI Q&A

2026-07-14

EPSS Evaluated

2026-08-02

NVD

CVE-2026-58637

EUVD

EUVD-2026-44314

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_10_1607	to 10.0.14393.9339 (exc)
microsoft	windows_10_1607	to 10.0.14393.9339 (exc)
microsoft	windows_10_1809	to 10.0.17763.9020 (exc)
microsoft	windows_10_1809	to 10.0.17763.9020 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8875 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8875 (exc)
microsoft	windows_server_2025	to 10.0.26100.33158 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8875 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8875 (exc)
microsoft	windows_server_2022	to 10.0.20348.5386 (exc)
microsoft	windows_server_2016	to 10.0.14393.9339 (exc)
microsoft	windows_server_2019	to 10.0.17763.9020 (exc)

Helpful Resources

Exploitability

CWE

KEV

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

Executive Summary

CVE-2026-58637 is a use-after-free vulnerability in the Windows Client-Side Caching (CSC) Service. This type of vulnerability occurs when a program continues to use memory after it has been freed, which can lead to unexpected behavior or exploitation.

In this case, an authorized attacker with local access to the system can exploit this flaw to elevate their privileges. This means the attacker could gain higher-level permissions on the system, potentially allowing them to perform actions they would not normally be able to.

Impact Analysis

If you are using a system with the Windows Client-Side Caching (CSC) Service, this vulnerability could impact you in the following ways:

An attacker with local access to your system could exploit this vulnerability to gain elevated privileges.
With elevated privileges, the attacker could execute arbitrary code, install malicious software, or access sensitive data.
This could lead to a full compromise of the affected system, allowing the attacker to take control of it.

The CVSS base score of 7.0 indicates a high severity, meaning the vulnerability poses a significant risk if exploited.

Compliance Impact

This vulnerability could impact compliance with common standards and regulations in the following ways:

GDPR: If the affected system processes personal data of EU citizens, a successful exploit could lead to unauthorized access or disclosure of this data. This may result in a violation of GDPR's data protection requirements, potentially leading to fines or legal action.
HIPAA: For organizations handling protected health information (PHI), this vulnerability could allow an attacker to access or modify sensitive health data. This would violate HIPAA's security and privacy rules, potentially resulting in penalties.
Other standards: Many compliance frameworks (e.g., ISO 27001, NIST) require organizations to protect systems from known vulnerabilities. Failure to patch or mitigate this vulnerability could result in non-compliance with these standards.

To maintain compliance, it is critical to apply security updates or mitigations provided by Microsoft to address this vulnerability.

Mitigation Strategies

Apply the security update provided by Microsoft for CVE-2026-58637. This update addresses the use-after-free vulnerability in the Windows Client-Side Caching (CSC) Service.

To obtain the update, visit the Microsoft Update Guide linked in the resources and follow the instructions for patching affected systems.

Ensure all Windows systems are updated to the latest version or apply the specific patch for this CVE.
Monitor Microsoft's security advisories for any additional guidance or updates related to this vulnerability.

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