Ah, Patch Tuesday. That magical second Tuesday of every month when Microsoft drops a metric ton of security updates and admins worldwide collectively groan. November 2025’s edition is a doozy: 63 vulnerabilities patched, including one actively exploited zero-day that’s already being used in the wild.

Time to clear your calendar and start patching, folks.

The Zero-Day: CVE-2025-62215

The star of this month’s shit show is CVE-2025-62215, a Windows Kernel privilege escalation vulnerability that’s being actively exploited.

Here’s the technical breakdown:

• Vulnerability type: Race condition in Windows Kernel
• Impact: Elevation of privileges from user to SYSTEM
• Attack complexity: Requires winning a race condition
• User interaction: Not required
• CVSS score: 7.0

A race condition vulnerability means the attacker has to manipulate the timing of operations to trigger a specific code path that grants elevated privileges. It’s not guaranteed to work on the first try, but once an attacker figures out how to reliably trigger it, they’ve got SYSTEM privileges.

SYSTEM privileges on Windows is game over. It’s the highest privilege level, even higher than Administrator. An attacker with SYSTEM can do literally anything: install malware, modify security settings, steal data, create persistence, disable security tools—you name it.

Microsoft says the vulnerability involves “concurrent execution using shared resource with improper synchronization”, which is a fancy way of saying two threads tried to use the same resource at the same time and the kernel didn’t handle it properly. The result? Exploitable race condition.

Microsoft attributed the discovery to their own Threat Intelligence Center (MSTIC) and Security Response Center (MSRC), which usually means they found it being actively exploited in the wild and reverse-engineered the attack.

The Rest of the Vulnerabilities

Beyond the zero-day, Microsoft patched 62 additional vulnerabilities:

Severity breakdown:

• 5 Critical
• 58 Important

Vulnerability categories:

• 29 Elevation of Privilege
• 16 Remote Code Execution
• 11 Information Disclosure
• 3 Denial of Service
• 2 Security Feature Bypass
• 2 Spoofing

Some highlights from the Critical vulnerabilities:

CVE-2025-59504: Microsoft Azure Monitor Agent RCE (CVSS 4.6/temporal 3.4). Allows unauthorized attacker to execute code locally on Azure VMs.

CVE-2025-62204: SharePoint Server RCE. Affects SharePoint 2016, 2019, and Subscription Edition. Authorized attackers can execute code remotely.

CVE-2025-60724: GDI+ RCE (CVSS 9.8). Network-based attack requiring no user interaction or privileges. Attackers can trigger RCE through crafted image or metafile content.

CVE-2025-62214: Visual Studio RCE (CVSS 6.7). Heap-based buffer overflow that could compromise developer endpoints and build systems.

CVE-2025-62199: Microsoft Office RCE (CVSS 7.8). Another Office vulnerability exploitable through malicious documents.

Products Affected

This Patch Tuesday touches damn near everything Microsoft makes:

• Windows (all versions: 10, 11, Server 2016, 2019, 2022, etc.)
• Microsoft Office
• SharePoint Server
• Azure Monitor Agent
• Microsoft SQL Server
• Exchange Server
• Visual Studio
• .NET Framework

If you’re running Microsoft products (and who isn’t?), you’ve got patching to do.

CISA and the KEV Catalog

While I haven’t seen confirmation that CVE-2025-62215 was added to CISA’s Known Exploited Vulnerabilities catalog yet, it’s only a matter of time. CISA typically adds actively exploited vulnerabilities to the KEV, which triggers mandatory patching deadlines for federal agencies.

For private sector organizations, KEV inclusion is a strong signal that you should prioritize patching immediately.

The Patch Management Problem

Here’s the reality: 63 vulnerabilities is a lot to test and deploy, especially for large, complex environments with custom applications and legacy systems. But that zero-day is already being exploited, so you can’t just sit on it.

This is the eternal patch management dilemma: patch too quickly without testing and you might break production systems. Patch too slowly and you leave yourself vulnerable to active exploitation.

The recommended approach:

1. Comprehensive asset discovery: Know what systems you have and which are affected. 2. Risk-based prioritization: Start with CVE-2025-62215 (actively exploited), then Critical RCEs, then everything else. 3. Staged testing and deployment: Test in dev/staging environments first, but don’t let testing delay critical patches for weeks. 4. Phased rollout: Deploy to critical systems first, then roll out to the rest of the environment. 5. Network segmentation: Mitigate RCE blast radius by ensuring attackers can’t easily move laterally even if they exploit a vulnerability. 6. Monitoring: Watch for post-update anomalies, failed patches, or signs of exploitation.

Why Attackers Love Windows Kernel Vulns

Kernel-level vulnerabilities are gold for attackers because the kernel is the core of the operating system. Everything runs through it. If you can exploit the kernel, you can:

• Bypass security controls like antivirus and EDR
• Hide malware at the rootkit level
• Escalate privileges to SYSTEM
• Access memory and processes of all running applications
• Disable security monitoring

Privilege escalation vulnerabilities like CVE-2025-62215 are particularly valuable in multi-stage attacks. An attacker might gain initial access through phishing or a web app exploit (which gives them user-level access), then use a kernel exploit to escalate to SYSTEM and take full control of the machine.

The Zero-Day Economy

Microsoft doesn’t say who’s exploiting CVE-2025-62215 or how. That information is usually kept confidential to avoid tipping off other threat actors or revealing sensitive intelligence sources and methods.

But we can make some educated guesses. Kernel privilege escalation zero-days are typically used by:

• Nation-state APT groups (China, Russia, Iran, North Korea)
• Sophisticated cybercriminal organizations
• Surveillance vendors selling exploits to governments

These aren’t script kiddies. This is targeted, sophisticated exploitation by well-resourced actors.

The fact that Microsoft’s own threat intelligence team discovered it suggests it was being used selectively against high-value targets, not sprayed across the internet. That’s actually good news in a weird way—it means most organizations probably haven’t been hit yet. But once the patch is released, security researchers will reverse-engineer it, and working exploits will be publicly available within days or weeks.

That’s your patching window: the brief period between patch release and public exploit availability. Use it wisely.

What You Need to Do

1. Patch CVE-2025-62215 immediately, especially on high-value systems like domain controllers, database servers, and admin workstations. 2. Review the full list of CVEs and prioritize based on your environment and risk profile. 3. Test patches in non-production environments if possible, but don’t let testing delay critical security updates. 4. Monitor for signs of exploitation: unusual privilege escalation, unexpected SYSTEM-level processes, disabled security tools, or other anomalies. 5. Check your EDR/SIEM logs for indicators of compromise related to kernel exploits: suspicious driver loads, debug privileges being granted, or other telltale signs. 6. Document your patching timeline for compliance and audit purposes. If you get breached and auditors find out you delayed patching a known-exploited zero-day, that’s going to be a bad day.

The November 2025 Patch Tuesday Takeaway

Sixty-three vulnerabilities, one actively exploited zero-day, impacts across the entire Microsoft ecosystem. It’s a heavy lift, but it’s also just another month in enterprise IT security.

Patch management isn’t glamorous. It doesn’t get headlines (except when companies don’t do it and get breached). But it’s one of the most effective security controls you can implement. The vast majority of successful cyberattacks exploit known vulnerabilities that have patches available.

Microsoft released the patches. Now it’s on you to deploy them before the bad guys figure out how to exploit them at scale.

Get patching, folks.

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