Microsoft’s October 2025 Patch Tuesday

Summary

Microsoft’s October 2025 Patch Tuesday delivers an extensive security update addressing 175 vulnerabilities across multiple platforms including Windows Server (2008–2025), Windows 10/11 (25H2), Azure Entra ID, WSUS, Microsoft Office, SharePoint, and Google Chromium.
Out of these, 15 are critical, 158 important, and 2 moderate, spanning key impact areas such as Elevation of Privilege (84), Remote Code Execution (29), Information Disclosure (26), Denial of Service (11), Security Feature Bypass (10), Tampering (1), and Spoofing (14).
Additionally, 21 non-Microsoft CVEs were patched, bringing the total to 196 vulnerabilities for this cycle, with 20 actively exploited in the wild—highlighting the urgent need for immediate patching.

Vulnerability Details

Actively Exploited and Zero-Day Vulnerabilities

• CVE-2025-24990: A Windows Agere Modem Driver flaw allowing administrator-level privilege escalation. Microsoft removed the vulnerable driver, which disables dependent fax modem hardware.
• CVE-2025-59230: Improper access control in Windows Remote Access Connection Manager allows SYSTEM-level privilege escalation.
• CVE-2025-47827: IGEL OS Secure Boot bypass enables mounting of unverified SquashFS root filesystems, compromising system integrity.

Critical Vulnerabilities of Note

• CVE-2025-59246: Azure Entra ID privilege escalation vulnerability.
• CVE-2025-59287: Windows Server Update Service (WSUS) remote code execution flaw via unsafe deserialization.
• CVE-2025-0033: AMD EPYC SEV-SNP race condition vulnerability—permits hypervisor-level RMP manipulation, partially patched with more fixes pending.
• CVE-2025-2884: TPM 2.0 Reference Implementation out-of-bounds read vulnerability leading to potential data exposure.
• CVE-2025-59489: Unity Engine Editor argument injection enabling unauthorized code execution and data exfiltration across Windows, macOS, Linux, and Android.

Together, these vulnerabilities expose critical attack vectors across Windows kernel, driver components, and cloud identity frameworks, stressing the need for rapid remediation.

Recommendations

1. Perform an exposure audit to locate internet-facing or vulnerable services and apply the latest patches immediately.
2. Prioritize actively exploited CVEs—CVE-2025-24990, CVE-2025-59230, and CVE-2025-47827—to minimize risk of active intrusion.
3. Maintain configuration hygiene to prevent re-exposure after patching; verify updates, remove deprecated dependencies, and monitor new assets.
4. Implement network segmentation to isolate high-risk systems and reduce lateral movement potential.

5. Apply least-privilege access policies across users and service accounts to limit privilege escalation opportunities.

MITRE ATT&CK TTPs

References

• Microsoft Security Update Guide – CVE-2025-24052
• Microsoft Security Update Guide – CVE-2025-24990
• Microsoft Security Update Guide – CVE-2025-59230
• Microsoft Security Update Guide – CVE-2025-59287

• MITRE ATT&CK Framework – https://attack.mitre.org

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