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Microsoft Patch Tuesday
January 2019

Microsoft's January 2019 Patch Tuesday fixes 51 vulnerabilities across Windows, Microsoft Office and Developer Tools - 6 rated Critical, 3 publicly disclosed before the patch shipped. No active exploitation this month, so lead with the 6 Critical remote code execution fixes.

Released January 8, 2019, 10:00 PT3 publicly disclosed69 KB articles to deploy

January 2019 Patch Tuesday at a glance

51
Microsoft CVEs
excl. Edge & Azure Linux
6
Critical
12% of the release
0
Actively exploited
none this month
3
Publicly disclosed
known before the patch
9.8
Highest CVSS
CVE-2019-0547
69
KB articles
what you actually deploy

Why this number differs from other roundups. Microsoft's January 2019 release document lists 71 entries. 18 are Azure Linux (Mariner) OS package updates and 2 are republished Chromium fixes for Edge - neither is a Microsoft product vulnerability. The 51 above is the real Patch Tuesday set. See the breakdown →

Priority order

Patch these first

Ranked by exploitation reality, not score alone. Nothing is under active attack this month, so the Critical remote-code-execution fixes lead.

The numbers

What’s in this release

Where the 71 entries actually come from

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

51 Microsoft products18 Azure Linux (Mariner)2 Edge (Chromium)

Severity

Microsoft channel only · 51 CVEs

January 2019 severity breakdown
Critical6
Important41
Moderate3
Low0
Unrated1

Impact type

What an attacker gains if it works

January 2019 impact breakdown
Remote Code Execution21
Information Disclosure12
Elevation of Privilege10
Spoofing5
Denial of Service2
Other1

Most-affected components

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

Microsoft JET Database Engine11Microsoft Windows6Microsoft Office4Microsoft Office SharePoint4Windows Kernel4Microsoft Scripting Engine3ASP.NET2Microsoft Exchange Server2Team Foundation Server2Visual Studio2Windows Hyper-V2.NET Framework1
Every patch

Browse all 71 entries

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

Showing 51 of 51
51 Microsoft vulnerabilities in the January 2019 Patch Tuesday, sortable by severity, CVSS and exploit status.
TitleStatusKB
ImportantCVE-2019-0646Team Foundation Server Cross-site Scripting VulnerabilitySpoofing-DisclosedTeam Foundation Server—
ModerateCVE-2019-0647Team Foundation Server Information Disclosure VulnerabilityInfo Disc.-DisclosedTeam Foundation Server—
ImportantCVE-2019-0579Jet Database Engine Remote Code Execution VulnerabilityRCE7.8DisclosedMicrosoft JET Database Engine4480116 +13
CriticalCVE-2019-0539Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4480116 +5
CriticalCVE-2019-0567Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4480116 +5
CriticalCVE-2019-0568Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4480116 +1
ImportantCVE-2019-0543Microsoft Windows Elevation of Privilege VulnerabilityEoP7.8More likelyMicrosoft Windows4480116 +13
ImportantCVE-2019-0572Windows Data Sharing Service Elevation of Privilege VulnerabilityEoP7.8More likelyMicrosoft Windows4480116 +5
ImportantCVE-2019-0573Windows Data Sharing Service Elevation of Privilege VulnerabilityEoP7.8More likelyMicrosoft Windows4480116 +5
ImportantCVE-2019-0574Windows Data Sharing Service Elevation of Privilege VulnerabilityEoP7.8More likelyMicrosoft Windows4480116 +5
ImportantCVE-2019-0541MSHTML Engine Remote Code Execution VulnerabilityRCE7.5More likelyInternet Explorer2553332 +15
ImportantCVE-2019-0552Windows COM Elevation of Privilege VulnerabilityEoP7.0More likelyWindows COM4480116 +7
ImportantCVE-2019-0555Microsoft XmlDocument Elevation of Privilege VulnerabilityEoP7.0More likelyMicrosoft XML4486993 +9
ImportantCVE-2019-0569Windows Kernel Information Disclosure VulnerabilityInfo Disc.5.5More likelyWindows Kernel4480116 +13
ImportantCVE-2019-0586Microsoft Exchange Memory Corruption VulnerabilityRCE-More likelyMicrosoft Exchange Server4471389
CriticalCVE-2019-0550Windows Hyper-V Remote Code Execution VulnerabilityRCE7.6—Windows Hyper-V4480116 +1
CriticalCVE-2019-0551Windows Hyper-V Remote Code Execution VulnerabilityRCE7.6—Windows Hyper-V4480116 +4
ImportantCVE-2019-0570Windows Runtime Elevation of Privilege VulnerabilityEoP7.8—Microsoft Windows4480116 +9
ImportantCVE-2019-0571Windows Data Sharing Service Elevation of Privilege VulnerabilityEoP7.8—Microsoft Windows4480116 +5
ImportantCVE-2019-0536Windows Kernel Information Disclosure VulnerabilityInfo Disc.4.7—Windows Kernel4480116 +13
ImportantCVE-2019-0549Windows Kernel Information Disclosure VulnerabilityInfo Disc.4.7—Windows Kernel4480116 +13
ImportantCVE-2019-0553Windows Subsystem for Linux Information Disclosure VulnerabilityInfo Disc.4.7—Windows Subsystem for Linux4480116 +3
ImportantCVE-2019-0554Windows Kernel Information Disclosure VulnerabilityInfo Disc.4.7—Windows Kernel4480116 +13
ImportantCVE-2019-0537Microsoft Visual Studio Information Disclosure VulnerabilityInfo Disc.-—Visual Studio4476698 +1
ImportantCVE-2019-0545.NET Framework Information Disclosure VulnerabilityInfo Disc.-—.NET Framework4480056 +13
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 69 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 51 vulnerabilities in January 2019, across Windows, Microsoft Office, Developer Tools and Browser. 6 are rated Critical, 3 were publicly disclosed before the patch shipped, and 0 were already being exploited. Note that Microsoft's release document lists 71 entries in total, but 18 of those are Azure Linux package updates and 2 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 2 Edge entries alongside Microsoft product fixes would inflate the headline number and imply work for your Windows Update rings that does not exist.