CVE-2025-59275 Overview
CVE-2025-59275 is a local privilege escalation vulnerability in Windows Authentication Methods. Improper validation of a specified input type allows an authorized attacker to elevate privileges on the affected host. The flaw is tracked under CWE-122 (Heap-based Buffer Overflow) and affects supported Windows client and server versions from Windows 10 1507 through Windows Server 2025. Microsoft published the advisory on October 14, 2025.
Critical Impact
An authenticated local attacker can gain elevated privileges, resulting in high impact to confidentiality, integrity, and availability on the compromised system.
Affected Products
- Microsoft Windows 10 (1507, 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (22H2, 23H2, 24H2)
- Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-10-14 - Microsoft releases security update for CVE-2025-59275
- 2025-10-14 - CVE-2025-59275 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-59275
Vulnerability Analysis
The vulnerability resides in the Windows Authentication Methods subsystem. Microsoft describes the issue as improper validation of a specified type of input, which enables privilege escalation from a low-privileged local context to a higher privilege level. NVD categorizes the root weakness under CWE-122, indicating a heap-based buffer overflow reachable through the authentication input path.
Exploitation requires local access and valid low-privileged credentials on the target host. No user interaction is required, and the attack scope is unchanged. Successful exploitation yields high confidentiality, integrity, and availability impact, consistent with attacker-controlled code execution in a privileged security context.
Root Cause
The underlying defect is a failure to validate the type of data supplied to a Windows Authentication Methods routine. When the affected component processes crafted input on the heap without enforcing the expected type or size constraints, adjacent heap metadata or object pointers can be corrupted. This corruption is the mechanism that permits privilege elevation.
Attack Vector
An attacker who already has a foothold on the machine, such as a compromised standard user account or a session obtained through phishing, malware, or lateral movement, invokes the vulnerable authentication path with malformed input. The resulting heap corruption is leveraged to hijack execution flow and run code in a privileged context, typically enabling SYSTEM-level access.
No public proof-of-concept exploit is listed in the enriched data, and the vulnerability is not currently tracked on the CISA Known Exploited Vulnerabilities catalog.
No verified public exploit code is available. Refer to the Microsoft Security Update for CVE-2025-59275 for authoritative technical guidance.
Detection Methods for CVE-2025-59275
Indicators of Compromise
- Unexpected creation of processes running as NT AUTHORITY\SYSTEM from parent processes owned by standard users.
- Crashes or exceptions logged for components tied to Windows Authentication Methods, including lsass.exe and related security packages.
- New local accounts, group membership changes, or scheduled tasks created shortly after anomalous authentication activity.
Detection Strategies
- Monitor Windows Security and System event logs for abnormal authentication package behavior and repeated malformed authentication attempts.
- Alert on token manipulation and integrity-level transitions where a medium-integrity process spawns a high or system-integrity child.
- Correlate local logon events (Event ID 4624 type 2) with subsequent privileged process creation (Event ID 4688) from the same session.
Monitoring Recommendations
- Enable command-line auditing and PowerShell script block logging to capture post-exploitation activity following privilege gain.
- Forward endpoint telemetry to a centralized SIEM or data lake and retain authentication and process events for at least 90 days.
- Baseline the frequency of privilege escalation and authentication anomalies per host so deviations trigger investigation.
How to Mitigate CVE-2025-59275
Immediate Actions Required
- Apply the October 2025 Microsoft security update for every affected Windows client and server SKU listed in the advisory.
- Prioritize patching of domain controllers, jump hosts, and multi-user servers where local access by standard users is common.
- Audit local and interactive logon rights and remove unnecessary accounts to reduce the pool of potential attackers.
Patch Information
Microsoft has released fixes for all affected versions through the Microsoft Security Update Guide for CVE-2025-59275. Deploy the corresponding cumulative update via Windows Update, Windows Server Update Services (WSUS), or Microsoft Intune. Legacy platforms such as Windows Server 2008 and 2012 require the Extended Security Update (ESU) channel.
Workarounds
- No official workarounds have been published by Microsoft; patching is the required remediation.
- As a compensating control, restrict interactive and network logon rights on sensitive hosts through Group Policy until updates are deployed.
- Enforce application allowlisting and least-privilege policies to limit which binaries a standard user can execute against authentication interfaces.
# Verify patch installation on a Windows host (PowerShell)
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 10
# Query for the specific KB associated with CVE-2025-59275 after identifying it in the MSRC advisory
wmic qfe list brief /format:table
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
