Overview: What is Patch Tuesday?

Patch Tuesday is the day Microsoft releases its regular monthly security updates, usually on the second Tuesday of the month. On this day, Microsoft discloses fixed security flaws and makes the corresponding patches available.

For January 2026, the release includes:

114 vulnerabilities in total

3 zero-day vulnerabilities that are already being actively exploited

If you use Windows at home or at work, this affects you directly.

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Key terms in plain language

To understand the headlines, you only need a few basic concepts:

What is a vulnerability?

A vulnerability is a defect in software. Attackers can abuse it to:

crash programs or entire systems

steal data

install malware

take control of your device

What does zero-day mean?

A zero-day vulnerability is a security flaw that attackers are already exploiting before a patch exists or before it is publicly known.

In January 2026 there are three such vulnerabilities. This is serious, but not a reason to panic – as long as you update promptly.

Critical vs. important

Microsoft places vulnerabilities into severity categories, typically:

Critical: Often allows remote code execution. Attackers can install malware without you doing anything.

Important: Still dangerous, but the attacker usually needs an extra step from you (for example, you opening a file).

Both categories matter, but critical vulnerabilities should be patched first.

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Which systems are usually affected?

The exact advisories change each month, but for a large Patch Tuesday like January 2026 the following components are typically involved:

Windows 10 and Windows 11 (all supported editions)

Windows Server (for example 2019, 2022)

Microsoft Office and Microsoft 365 Apps

Browsers such as Microsoft Edge

Components like .NET, Visual Studio, or Azure services

Important: If your system still receives updates from Microsoft, it is almost certainly affected and should be patched.

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Why these 3 zero-days deserve special attention

Zero-day flaws are problematic because attackers have a head start. Usually this means:

Attacks have already been observed in the wild.

Security tools often do not detect these attacks reliably yet.

Criminals quickly copy working attack techniques.

So you should not wait for weeks. Install the updates within a few days.

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How to check whether your Windows system is up to date

On Windows 10

1.Open the Start menu.

2.Click Settings (gear icon).

3.Select Update & Security.

4.Open Windows Update.

5.Click Check for updates.

If you see that updates are available or a restart is required, install them as soon as you can.

On Windows 11

1.Open the Start menu.

2.Open Settings.

3.Click Windows Update in the left pane.

4.Click Check for updates.

Enable automatic updates if your local policies allow it.

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Recommended update strategy for home users

For home users, a simple and robust process is enough:

1.Turn on automatic updates

Let Windows download and install updates on its own.

2.Do not postpone restarts forever

Many fixes only take effect after a reboot.

3.Update your browser and Office as well

- Edge, Chrome, and Firefox usually update automatically.

- Still, check periodically via Help → About.

4.Avoid shady "driver" or "update" tools

Stick to Windows Update and the built-in update features of your software.

5.Keep backups

At least back up important documents regularly to an external drive or a cloud service.

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Update strategy for small businesses

Small organisations often do not have a dedicated security team. A clear, lightweight routine helps a lot:

1.Create an inventory

- Which Windows versions are in use?

- Which Office version?

- Do you run servers (file servers, terminal servers, application servers)?

2.Set up a small test group

- 1–3 devices (or a small user group) receive updates first.

- Watch them for 1–2 days for serious issues.

3.Roll out to all other systems

- Define a fixed patch slot (for example, Thursday evening after Patch Tuesday).

- Inform staff that restarts will be required.

4.Treat servers with extra care

- Always create a current backup before patching.

- Patch outside business hours if possible.

- Start with less critical servers, then move to central systems.

5.Document briefly

Note the date, systems, and any special incidents. This is useful for troubleshooting and audits.

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Can you tell if you were hit by one of the zero-days?

Honestly: In most cases, you cannot tell with certainty. Many attacks are quiet and leave little visible trace.

Still, you can do a few things:

Keep antivirus and EDR solutions updated

Use a reputable security product and let it update automatically.

Check the Windows Event Viewer occasionally

Look for frequent crashes or unusual error messages.

Take unusual behaviour seriously

- Programs suddenly refuse to start

- The PC is constantly busy without a clear reason

- Unknown programs appear on the desktop

If you suspect a compromise, get help from a professional or your IT support.

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Common myths about Windows updates

Myth 1: "I never install updates, then nothing breaks."

In reality, the risk that something breaks goes up – namely your data or your device due to malware.

Myth 2: "Antivirus is enough."

Without updates, the door stays open, and your antivirus cannot catch everything.

Myth 3: "I am too unimportant to be hacked."

Most attacks are automated. Systems are scanned and exploited regardless of who owns them.

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Practical to-do list for today

1.Open Windows Update and check for updates.

2.Install all offered security updates.

3.Restart your PC or server.

4.Update your browser and Office.

5.Quickly verify that your most important applications still work as expected.

If you repeat these steps after every Patch Tuesday, you greatly reduce your risk – including in large update waves such as January 2026 with three zero-day flaws and 114 fixed vulnerabilities.

Microsoft January 2026 Patch Tuesday: 3 Zero-Days and 114 Vulnerabilities Explained Clearly