CVE-2024-26248: Windows 10 Privilege Escalation Vulnerability

CVE-2024-26248 Overview

CVE-2024-26248 is an elevation of privilege vulnerability in the Windows Kerberos authentication protocol. Microsoft disclosed the issue as part of its April 2024 security updates. The flaw affects a broad range of Windows client and server releases, including Windows 10, Windows 11, and Windows Server versions from 2008 through 2022 23H2.

The vulnerability is categorized under [CWE-303] (Incorrect Implementation of Authentication Algorithm). An authenticated attacker on an adjacent or reachable network can abuse the weakness to gain higher privileges within the Kerberos authentication flow.

Critical Impact

Successful exploitation allows an authenticated attacker to elevate privileges, potentially impacting confidentiality, integrity, and availability of the affected Windows host.

Affected Products

• Microsoft Windows 10 (1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (21H2, 22H2, 23H2)
• Microsoft Windows Server 2008, 2012, 2012 R2, 2016, 2019, 2022, and 2022 23H2

Discovery Timeline

• 2024-04-09 - CVE-2024-26248 published to NVD and included in Microsoft's Patch Tuesday release
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-26248

Vulnerability Analysis

The vulnerability resides in the Windows Kerberos implementation, which handles authentication for domain-joined systems. Kerberos issues tickets that clients present to services to prove identity and negotiate access. A defect in the authentication algorithm allows an attacker who already holds low-level credentials to elevate their privileges on the target system.

Microsoft categorizes the flaw as an elevation of privilege issue rather than remote code execution. However, the resulting impact on confidentiality, integrity, and availability is significant because Kerberos underpins access decisions across the Windows ecosystem, including Active Directory environments.

The attack complexity is described as high, meaning exploitation requires specific conditions such as network positioning or timing. An EPSS probability of 1.034% (60th percentile) indicates modest but non-trivial interest in exploitation compared to the broader CVE population.

Root Cause

The root cause maps to [CWE-303], an incorrect implementation of an authentication algorithm within Kerberos. The Kerberos subsystem does not correctly enforce authentication checks under specific conditions. This allows a low-privileged account to influence authentication outcomes and obtain elevated rights on the target host.

Attack Vector

Exploitation requires network access and a valid set of low-privilege credentials. The attacker interacts with the Kerberos protocol on a vulnerable Windows system and manipulates the authentication exchange to gain elevated privileges. User interaction is not required. Because the flaw operates within a core authentication protocol, successful exploitation may grant broad access to resources protected by Kerberos tickets on the affected host.

No public proof-of-concept code has been published, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog at the time of writing. Refer to the Microsoft CVE-2024-26248 Update Guide for authoritative technical details.

Detection Methods for CVE-2024-26248

Indicators of Compromise

• Unexpected Kerberos ticket requests (AS-REQ, TGS-REQ) originating from low-privileged accounts followed by access to sensitive resources.
• Authentication events with anomalous encryption types or ticket lifetimes in Windows Security event logs.
• Sudden privilege changes on Windows hosts shortly after Kerberos authentication events.

Detection Strategies

• Monitor Windows Security event IDs 4768, 4769, and 4770 for unusual ticket-granting activity tied to non-administrative accounts.
• Correlate Kerberos authentication traffic with subsequent process creation events (event ID 4688) showing privileged binary execution.
• Baseline normal Kerberos activity per host and flag deviations in ticket volume, source, or target service principal names.

Monitoring Recommendations

• Ingest domain controller and endpoint authentication logs into a centralized analytics platform for correlation across the Active Directory estate.
• Enable auditing for Kerberos service ticket operations and account logon events on all Windows Servers and endpoints.
• Track patch compliance for the April 2024 cumulative updates across all Windows client and server SKUs listed in the affected products.

How to Mitigate CVE-2024-26248

Immediate Actions Required

• Apply the April 2024 Microsoft security updates to all affected Windows client and server systems without delay.
• Prioritize patching of domain controllers and systems handling privileged Kerberos authentication.
• Audit accounts with local logon rights on Windows systems and remove unnecessary low-privilege access that could be leveraged for exploitation.

Patch Information

Microsoft released fixes for CVE-2024-26248 in the April 2024 Patch Tuesday cycle. The updates address the incorrect authentication implementation in the Kerberos component across all supported Windows versions. Refer to the Microsoft CVE-2024-26248 Update Guide for KB article numbers and download links specific to each affected product.

Workarounds

• No official workarounds have been published by Microsoft; installing the security update is the recommended remediation.
• Restrict network access to Windows systems from untrusted network segments to reduce exposure until patches are applied.
• Enforce strong tiered administration practices to limit the value of any credentials an attacker may obtain for exploitation.

# Verify the April 2024 update is installed on a Windows host
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