Patch Tuesday + AI: Close Zero-Day Windows Gaps Fast

Most companies get Patch Tuesday wrong in a very predictable way: they treat it like a calendar event instead of an incident response trigger.

Microsoft’s December 2025 release fixes 57 CVEs, including one actively exploited zero-day and two publicly disclosed zero-days. That’s not “just patching.” It’s a time-boxed race where your attackers know what to try, your endpoints are spread across the org, and your IT change windows are shrinking because it’s late December.

This post is part of our AI in Cybersecurity series, and I’m going to take a firm stance: AI isn’t optional anymore for vulnerability response. Not because humans aren’t capable—but because humans can’t keep pace with the volume, the prioritization decisions, and the follow-through required when exploitability changes by the hour.

What December 2025 Patch Tuesday means in plain terms

Microsoft’s December 2025 Patch Tuesday is dominated by two patterns: privilege escalation and remote code execution (RCE). Specifically, the leading risk types by exploitation technique are:

• Elevation of privilege: 28 patches (49%)
• Remote code execution: 19 patches (34%)
• Information disclosure: 4 patches (7%)

Windows accounts for the biggest share of fixes (38), followed by Microsoft Office (14).

Here’s the operational takeaway: this month isn’t a single “apply updates” task. It’s a set of decisions about where compromise starts (Office/email), how it spreads (RCE), and how it sticks (privilege escalation to SYSTEM).

Why December patching is uniquely risky

December is when patch SLAs quietly degrade:

• Teams are short-staffed.
• Change freezes happen.
• Business leaders prioritize uptime for year-end processing.

Attackers know that. If you’ve ever wondered why “actively exploited” hits at the most inconvenient times, it’s because adversaries love predictable defender behavior.

The zero-days you should treat as response-worthy, not “routine updates”

This month includes three standout issues that deserve triage like security events.

CVE-2025-62221: Windows Cloud Files Mini Filter Driver (actively exploited)

Direct answer: If you run Windows endpoints, treat CVE-2025-62221 as a top-tier priority because it enables local privilege escalation to SYSTEM and has evidence of exploitation in the wild.

• Type: Elevation of privilege
• Severity: Important
• CVSS: 7.8
• What it does: authenticated attacker with low privileges can exploit a use-after-free to become SYSTEM
• Requirements: local access, low privileges, no user interaction, low complexity

Why I care about this class of bug: EoP is what turns “we detected something” into “they own the box.” Once attackers reach SYSTEM, they can disable controls, dump credentials, and pivot.

If you’re thinking, “But it’s local,” remember what modern intrusions look like:

• Initial access often happens through credentials, phishing, or a foothold on one endpoint.
• The next move is privilege escalation.
• Then persistence and lateral movement.

This is the privilege escalation step, and it’s being used.

CVE-2025-64671: GitHub Copilot for JetBrains (publicly disclosed)

Direct answer: If you allow developer tooling on corporate endpoints, you need to patch Copilot plugins quickly and audit terminal automation settings.

• Type: RCE via command injection
• Severity: Important
• CVSS: 8.4
• Exposure: publicly disclosed, no evidence of in-the-wild exploitation (yet)

The detail worth pausing on: exploitation can be triggered through untrusted files or MCP servers and can chain into terminal behavior—especially where auto-approve or overly permissive workflows exist.

This is an “AI meets endpoint security” moment. Developer environments are increasingly where:

• credentials live,
• production access is staged,
• and secrets accidentally end up.

Treat dev endpoints as high-value targets, not “special snowflakes” that don’t follow enterprise controls.

CVE-2025-54100: PowerShell command injection (publicly disclosed)

Direct answer: Patch PowerShell and tighten execution controls because social engineering remains the easiest delivery mechanism.

• Type: RCE via command injection
• Severity: Important
• CVSS: 7.8
• Requires: user interaction (victim runs a crafted command or file)

PowerShell is still the attacker’s favorite “built-in tool.” When a vulnerability intersects with PowerShell, the real-world risk climbs—not only because of the bug itself, but because PowerShell is already a common post-compromise utility.

Office preview pane is still a top attack surface—stop treating it like background noise

Two Office issues stand out because they hit the most reliable exploitation path in many enterprises: email content processing.

• CVE-2025-62554 (Critical, CVSS 8.4) – type confusion leading to RCE
• CVE-2025-62557 (Critical, CVSS 8.4) – use-after-free leading to RCE

These can be triggered by specially crafted emails or links, with the preview pane called out as an attack vector.

A blunt reality check: if your patch process can’t outpace “email arrival,” your org is exposed. And the preview pane problem keeps recurring—CrowdStrike notes it’s been a steady source of critical vulns with at least one critical issue most months this year.

Practical stance: prioritize by exposure path, not just CVSS

CVSS is useful, but it’s not the decision-maker by itself. A pragmatic prioritization stack for this month looks like:

1. Actively exploited (CVE-2025-62221)
2. Email/Office RCE paths (CVE-2025-62554, CVE-2025-62557)
3. Widely present scripting/admin tools (PowerShell CVE-2025-54100)
4. High-value population tooling (Copilot for JetBrains CVE-2025-64671 on dev machines)

That ordering reflects something security teams learn the hard way: the easiest exploit path beats the scariest score.

Where AI actually helps: making patching run like a security operation

AI in cybersecurity isn’t just “better alerts.” For Patch Tuesday, it’s about compressing the time between “a vulnerability exists” and “we’re measurably safer.”

1) AI-driven triage: from 57 CVEs to a workable queue

Direct answer: AI helps by turning a month’s worth of vulnerabilities into an ordered plan based on your environment, not generic severity labels.

A good AI-assisted workflow uses signals like:

• Asset criticality (finance workstation vs kiosk)
• Real exposure (is the vulnerable component installed and running?)
• Observed attacker behavior (privilege escalation and Office delivery are hot this month)
• Compensating controls (hardening, application control, EDR policy posture)

Instead of “patch everything equally,” you get a ranked remediation backlog that matches how your environment can actually be compromised.

2) AI-assisted detection: buying time when patching isn’t immediate

Direct answer: When patches can’t land same-day, AI-powered detection and response reduces dwell time by spotting exploit-like behavior and privilege escalation patterns.

This matters most in December, when you may have legitimate reasons for phased rollouts. AI-driven analytics can watch for:

• suspicious kernel/driver interactions consistent with local privilege escalation attempts
• unexpected PowerShell command patterns on user endpoints
• Office processes spawning abnormal child processes (a common RCE tell)

I’ve found that teams get the most value when they stop treating detection as “post-breach” and start treating it as patch-delay insurance.

3) AI-enabled automation: patch orchestration without chaos

Direct answer: AI makes patching faster by automating the boring parts—asset grouping, exception handling, rollout validation, and drift detection.

A practical automation playbook for this month:

• Ring-based deployment (pilot → broad → stragglers)
• Auto-create tickets for systems missing the December cumulative update
• Auto-escalate exceptions tied to exposed populations (email-heavy roles, admins, developers)
• Post-deploy checks to confirm:
  • update installed
  • Office components updated
  • PowerShell version baselined

Automation isn’t about removing human judgment; it’s about removing human bottlenecks.

A December-ready response plan (you can run next week)

Direct answer: Treat this Patch Tuesday like a mini-campaign with a 72-hour goal for high-risk fixes.

Here’s a concrete sequence that works well in real environments:

Step 1: Triage within 4 hours

• Identify endpoints affected by:
  • Windows Cloud Files Mini Filter Driver (CVE-2025-62221)
  • Microsoft Office (CVE-2025-62554 / CVE-2025-62557)
  • PowerShell (CVE-2025-54100)
  • Copilot for JetBrains (CVE-2025-64671)

Step 2: Patch the “blast-radius multipliers” first (24 hours)

• Admin and IT endpoints (privilege escalation payoff is highest)
• Email-heavy departments (finance, HR, exec assistants)
• Developer workstations (tools + secrets + access)

Step 3: Add temporary mitigations while rollout completes

If you can’t patch everything immediately, you can still reduce risk:

• Tighten PowerShell execution controls and script policy where feasible
• Restrict developer terminal auto-approve behaviors
• Harden Office/email handling (preview pane risk awareness, attachment controls)
• Increase monitoring on Office child-process activity and suspicious PowerShell usage

Step 4: Verify closure, don’t assume it

Verification is where many programs fail. Require proof:

• Patch compliance by device group
• A list of exceptions with expiration dates
• A control check for high-risk user populations

If you don’t measure closure, you don’t have closure.

What to do if “not everything has a patch” becomes your new normal

The article makes a point that experienced teams already live: some vulnerabilities won’t have clean patch paths, and even when they do, operational constraints slow you down.

This is why vulnerability management is shifting toward exposure management—understanding not just “what’s vulnerable,” but what’s reachable, exploitable, and impactful in your environment.

AI helps here by correlating:

• external threat activity,
• asset importance,
• identity and privilege paths,
• and observed security telemetry,

…so you can make decisions that reduce risk even when perfect patching isn’t realistic.

Snippet-worthy truth: A vulnerability only becomes a business incident when it meets your environment.

The next move: turn Patch Tuesday into a repeatable AI workflow

This month’s numbers—57 CVEs, one exploited zero-day, and recurring Office preview pane exposure—reinforce a simple point for our AI in Cybersecurity series: speed is a control.

If you want fewer fire drills in 2026, set a goal that’s measurable: “High-risk Patch Tuesday items are triaged the same day, prioritized by real exposure, and remediated or mitigated within 72 hours.” AI makes that achievable without burning out your team.

If you’re looking at your environment and thinking, “We can’t do that with spreadsheets and meetings,” you’re right. The forward-looking question is: what would your patch response look like if prioritization, validation, and exception handling ran at machine speed?