Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws

Today is Microsoft’s February 2026 Patch Tuesday with security updates for 58 flaws, including 6 actively exploited and three publicly disclosed zero-day vulnerabilities.

This Patch Tuesday also addresses five “Critical” vulnerabilities, 3 of which are elevation of privileges flaws and 2 information disclosure flaws.

The number of bugs in each vulnerability category is listed below:

• 25 Elevation of Privilege vulnerabilities
• 5 Security Feature Bypass vulnerabilities
• 12 Remote Code Execution vulnerabilities
• 6 Information Disclosure vulnerabilities
• 3 Denial of Service vulnerabilities
• 7 Spoofing vulnerabilities

When BleepingComputer reports on Patch Tuesday security updates, we only count those released by Microsoft today. Therefore, the number of flaws does not include 3 Microsoft Edge flaws fixed earlier this month.

As part of these updates, Microsoft has also begun to roll out updated Secure Boot certificates to replace the original 2011 certificates that are expiring in late June 2026.

“With this update, Windows quality updates include a broad set of targeting data that identifies devices and their ability to receive new Secure Boot certificates,” explains Microsoft in the Windows 11 update notes.

“Devices will receive the new certificates only after they show sufficient successful update signals, which helps ensures a safe and phased rollout.”

To learn more about the non-security updates released today, you can review our dedicated articles on the Windows 11 KB5077181 & KB5075941 cumulative updates and the Windows 10 KB5075912 extended security update.

6 actively exploited zero-days

This month’s Patch Tuesday fixes six actively exploited vulnerabilities, three of which are publicly disclosed.

Microsoft classifies a zero-day flaw as publicly disclosed or actively exploited while no official fix is available.

The six actively exploited zero-days are:

CVE-2026-21510 – Windows Shell Security Feature Bypass Vulnerability

Microsoft has patched an actively exploited Windows security feature bypass that can be triggered by opening a specially crafted link or shortcut file.

“To successfully exploit this vulnerability, an attacker must convince a user to open a malicious link or shortcut file.” explains Microsoft.

“An attacker could bypass Windows SmartScreen and Windows Shell security prompts by exploiting improper handling in Windows Shell components, allowing attacker‑controlled content to execute without user warning or consent,” continued Microsoft.

While Microsoft has not shared further details, it likely allows attackers to bypass the Mark of the Web (MoTW) security warnings.

Microsoft has attributed the discovery of the flaw to Microsoft Threat Intelligence Center (MSTIC), Microsoft Security Response Center (MSRC), Office Product Group Security Team, Google Threat Intelligence Group, and an anonymous researcher.

CVE-2026-21513 – MSHTML Framework Security Feature Bypass Vulnerability

Microsoft has patched an actively exploited MSHTML security feature bypass flaw in Windows.

“Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network,” explains Microsoft.

There are no details on how this was exploited.

This flaw was once again attributed to Microsoft Threat Intelligence Center (MSTIC), Microsoft Security Response Center (MSRC), Office Product Group Security Team, and Google Threat Intelligence Group.

CVE-2026-21514 – Microsoft Word Security Feature Bypass Vulnerability

Microsoft has patched a security feature bypass flaw in Microsoft Word that is actively exploited.

“An attacker must send a user a malicious Office file and convince them to open it,” warns Microsoft’s advisory.

“This update addresses a vulnerability that bypasses OLE mitigations in Microsoft 365 and Microsoft Office which protect users from vulnerable COM/OLE control,” continues Microsoft.

Microsoft says that the flaw cannot be exploited in the Office Preview Pane.

The flaw was again attributed to Microsoft Threat Intelligence Center (MSTIC), Microsoft Security Response Center (MSRC), Office Product Group Security Team, Google Threat Intelligence Group, and an anonymous researcher.

As no details have been released, it is unclear if CVE-2026-21510, CVE-2026-21513, and CVE-2026-21514 were exploited in the same campaign.

CVE-2026-21519 – Desktop Window Manager Elevation of Privilege Vulnerability

Microsoft has patched an actively exploited elevation of privileges flaw in the Desktop Window Manager.

“An attacker who successfully exploited this vulnerability could gain SYSTEM privileges,” warns Microsoft.

No details have been shared on how it was exploited.

Microsoft has attributed the discovery of the flaw to Microsoft Threat Intelligence Center (MSTIC) & Microsoft Security Response Center (MSRC).

CVE-2026-21525 – Windows Remote Access Connection Manager Denial of Service Vulnerability

Microsoft fixed an actively exploited denial of service flaw in the Windows Remote Access Connection Manager.

“Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally,’ explains Microsoft.

No details have been shared on why or how this flaw was exploited in attacks.

Microsoft has attributed the discovery of the flaw to the 0patch vulnerability research team.

CVE-2026-21533 – Windows Remote Desktop Services Elevation of Privilege Vulnerability

Microsoft has fixed an elevation of privileges in Windows Remote Desktop Services.

“Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally,” explains Microsoft.

No details have been shared on how this flaw was exploited.

Microsoft has attributed the discovery of the flaw to the Advanced Research Team at CrowdStrike.

Of the six zero-days, CVE-2026-21513, CVE-2026-21510, and CVE-2026-21514 were publicly disclosed.

Recent updates from other companies

Other vendors who released updates or advisories in February 2026 include:

While not a security update, Microsoft has started rolling out built-in Sysmon functionality in Windows 11 insider builds, which many Windows admins will find useful.

The February 2026 Patch Tuesday Security Updates

Below is the complete list of resolved vulnerabilities in the February 2026 Patch Tuesday updates.

To access the full description of each vulnerability and the systems it affects, you can view the full report here.

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