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Microsoft Patch Tuesday
February 2021

Microsoft's February 2021 Patch Tuesday fixes 56 vulnerabilities across Windows, Microsoft Office and Developer Tools - 11 rated Critical, 6 publicly disclosed before the patch shipped, one already exploited in the wild. Patch CVE-2021-1732 first.

Released February 9, 2021, 10:00 PT1 actively exploited6 publicly disclosed58 KB articles to deploy

February 2021 Patch Tuesday at a glance

56
Microsoft CVEs
excl. Edge & Azure Linux
11
Critical
20% of the release
1
Actively exploited
CVE-2021-1732
6
Publicly disclosed
known before the patch
9.8
Highest CVSS
CVE-2021-24074
58
KB articles
what you actually deploy

Why this number differs from other roundups. Microsoft's February 2021 release document lists 124 entries. 50 are Azure Linux (Mariner) OS package updates and 18 are republished Chromium fixes for Edge - neither is a Microsoft product vulnerability. The 56 above is the real Patch Tuesday set. See the breakdown →

The numbers

What’s in this release

Where the 124 entries actually come from

Most roundups quote a single number. These are three unrelated release streams.

56 Microsoft products50 Azure Linux (Mariner)18 Edge (Chromium)

Severity

Microsoft channel only · 56 CVEs

February 2021 severity breakdown
Critical11
Important43
Moderate2
Low0

Impact type

What an attacker gains if it works

February 2021 impact breakdown
Remote Code Execution21
Elevation of Privilege12
Information Disclosure8
Denial of Service7
Spoofing5
Security Feature Bypass3

Most-affected components

Where this month’s fixes concentrate - filter by any of them in the table below

Microsoft Office Excel4Microsoft Office SharePoint4Windows Kernel3Windows TCP/IP3.NET Core2Developer Tools2Microsoft Dynamics2Microsoft Exchange Server2Microsoft Windows Codecs Library2Role: Windows Fax Service2Skype for Business2Windows Event Tracing2
Every patch

Browse all 124 entries

Sorted by risk by default: exploited first, then publicly disclosed, then severity, then CVSS. Search by CVE, title, component or KB number.

Showing 56 of 56
56 Microsoft vulnerabilities in the February 2021 Patch Tuesday, sortable by severity, CVSS and exploit status.
TitleStatusKB
ImportantCVE-2021-1732Windows Win32k Elevation of Privilege VulnerabilityEoP7.8ExploitedWindows Kernel4601315 +3
ImportantCVE-2021-1727Windows Installer Elevation of Privilege VulnerabilityEoP7.8DisclosedMore likelyWindows Installer4601315 +13
CriticalCVE-2021-26701.NET Core Remote Code Execution VulnerabilityRCE8.1Disclosed.NET Core—
ImportantCVE-2021-1733Sysinternals PsExec Elevation of Privilege VulnerabilityEoP7.8DisclosedSysInternals—
ImportantCVE-2021-1721.NET Core and Visual Studio Denial of Service VulnerabilityDoS6.5DisclosedDeveloper Tools—
ImportantCVE-2021-24098Windows Console Driver Denial of Service VulnerabilityDoS5.5DisclosedWindows Console Driver4601315 +3
ImportantCVE-2021-24106Windows DirectX Information Disclosure VulnerabilityInfo Disc.5.5DisclosedWindows DirectX4601315 +3
CriticalCVE-2021-24074Windows TCP/IP Remote Code Execution VulnerabilityRCE9.8More likelyWindows TCP/IP4601315 +13
CriticalCVE-2021-24078Windows DNS Server Remote Code Execution VulnerabilityRCE9.8More likelyRole: DNS Server4601315 +11
CriticalCVE-2021-24094Windows TCP/IP Remote Code Execution VulnerabilityRCE9.8More likelyWindows TCP/IP4601315 +13
ImportantCVE-2021-24066Microsoft SharePoint Remote Code Execution VulnerabilityRCE8.8More likelyMicrosoft Office SharePoint4493194 +3
ImportantCVE-2021-24072Microsoft SharePoint Server Remote Code Execution VulnerabilityRCE8.8More likelyMicrosoft Office SharePoint4493194 +2
ImportantCVE-2021-1698Windows Win32k Elevation of Privilege VulnerabilityEoP7.8More likelyWindows Kernel4601315 +3
ImportantCVE-2021-24086Windows TCP/IP Denial of Service VulnerabilityDoS7.5More likelyWindows TCP/IP4601315 +13
CriticalCVE-2021-24077Windows Fax Service Remote Code Execution VulnerabilityRCE9.8—Role: Windows Fax Service4601315 +13
CriticalCVE-2021-24088Windows Local Spooler Remote Code Execution VulnerabilityRCE8.8—Windows Print Spooler Components4601315 +13
CriticalCVE-2021-24093Windows Graphics Component Remote Code Execution VulnerabilityRCE8.8—Microsoft Graphics Component4601315 +4
CriticalCVE-2021-1722Windows Fax Service Remote Code Execution VulnerabilityRCE8.1—Role: Windows Fax Service4601315 +13
CriticalCVE-2021-24112.NET Core Remote Code Execution VulnerabilityRCE8.1—.NET Core—
CriticalCVE-2021-24081Microsoft Windows Codecs Library Remote Code Execution VulnerabilityRCE7.8—Microsoft Windows Codecs Library4601315 +4
CriticalCVE-2021-24091Windows Camera Codec Pack Remote Code Execution VulnerabilityRCE7.8—Microsoft Windows Codecs Library4601315 +4
ImportantCVE-2021-1728System Center Operations Manager Elevation of Privilege VulnerabilityEoP8.8—System Center4601269
ImportantCVE-2021-24105Package Managers Configurations Remote Code Execution VulnerabilityRCE8.4—Developer Tools—
ImportantCVE-2021-1726Microsoft SharePoint Server Spoofing VulnerabilitySpoofing8.0—Microsoft Office SharePoint4493194 +3
ImportantCVE-2021-24067Microsoft Excel Remote Code Execution VulnerabilityRCE7.8—Microsoft Office Excel4493192 +4
Your move

What your IT team should do

The same five steps every month, in the order that reduces risk fastest.

Test the known-issue candidates

Check the Windows release health dashboard before promoting past ring 1, and have the rollback path written down before you need it. Kernel, networking and authentication fixes are the ones that historically break things.

12 Patch Management Best Practices for 2026 →

Verify installed state, then evidence it

Confirm the patch is actually present on each endpoint rather than trusting that "deployment succeeded". Keep the resulting report - it is the artefact auditors ask for, and reconstructing it later is far more work than capturing it now.

Patch Management: The Complete Guide →

Trinetri does steps two through five automatically - detecting the 58 KB articles across every endpoint, staging them in rings, verifying installed state and producing the compliance evidence. See patch management →

Archive

Previous Patch Tuesdays

Every month Microsoft has published back to January 2016, each with the same breakdown and the full CVE list.

Older months104 releases, October 2024 – January 2016
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Patch Tuesday FAQ

Patch Tuesday falls on the second Tuesday of every month, with updates going live at 10:00 a.m. Pacific Time. Microsoft introduced the practice in October 2003, following the Blaster worm, to cut distribution costs and give administrators a predictable cadence instead of patches arriving at random. The 10:00 a.m. timing is deliberate: it leaves a full working week to remediate before the weekend. Internally Microsoft calls it the "B" release; optional "C" and "D" preview releases follow later in the month. The next Patch Tuesday is November 10, 2026.

Microsoft fixed 56 vulnerabilities in February 2021, across Windows, Microsoft Office, Developer Tools and Azure. 11 are rated Critical, 6 were publicly disclosed before the patch shipped, and 1 was already being exploited. Note that Microsoft's release document lists 124 entries in total, but 50 of those are Azure Linux package updates and 18 are republished Chromium fixes for Edge, which is why other sources sometimes quote a much larger number.

Exploit Wednesday is the day after Patch Tuesday. Attackers compare the newly released patches against the previous version to locate the flaw each one fixes, then build working exploits from that difference - often within 24 to 48 hours. It is the reason the deployment window matters as much as the patch itself: every hour a Critical remote code execution fix sits undeployed is an hour of measurable exposure.

A workable target for most organisations: actively exploited vulnerabilities within 24 hours, publicly disclosed ones within 72 hours, remaining Critical fixes within seven days, and everything else within the month. CISA's Known Exploited Vulnerabilities catalogue sets binding deadlines for US federal agencies and is a reasonable benchmark for everyone else. Stage the rollout in rings rather than deploying everywhere at once, so a regression is caught on a pilot group instead of in production.

An out-of-band update is a patch released outside the monthly cycle because the risk will not wait for the next Patch Tuesday. Microsoft issues them for actively exploited flaws with no mitigation - most famously during the WannaCry outbreak in 2017, when it took the unusual step of patching versions of Windows that were already out of support.

Yes. Adobe aligned its releases with Patch Tuesday in November 2012, and both SAP's Security Patch Day and Oracle's quarterly Critical Patch Updates are coordinated to the same week. Part of the reason is defensive: staggered releases let attackers reverse-engineer one vendor's patch to find the same underlying flaw in another's still-unpatched product. For IT teams it means the second Tuesday is rarely just a Microsoft problem.

Edge is built on Chromium, so most of its security fixes originate with the Chromium project and are republished by Microsoft under their own CVE identifiers. They ship on Chromium's cadence rather than the Patch Tuesday cycle, and they are delivered by Edge's own updater rather than Windows Update. Counting the 18 Edge entries alongside Microsoft product fixes would inflate the headline number and imply work for your Windows Update rings that does not exist.