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Microsoft Patch Tuesday
April 2019

Microsoft's April 2019 Patch Tuesday fixes 74 vulnerabilities across Windows, Browser and Developer Tools - 17 rated Critical, 2 already exploited in the wild. Patch CVE-2019-0859 first.

Released April 9, 2019, 10:00 PT2 actively exploited35 KB articles to deploy

April 2019 Patch Tuesday at a glance

74
Microsoft CVEs
excl. Edge & Azure Linux
17
Critical
23% of the release
2
Actively exploited
CVE-2019-0859
0
Publicly disclosed
known before the patch
7.8
Highest CVSS
CVE-2019-0859
35
KB articles
what you actually deploy

Why this number differs from other roundups. Microsoft's April 2019 release document lists 89 entries. 14 are Azure Linux (Mariner) OS package updates and 1 are republished Chromium fixes for Edge - neither is a Microsoft product vulnerability. The 74 above is the real Patch Tuesday set. See the breakdown →

Priority order

Patch these first

Ranked by exploitation reality, not score alone. This month's exploited flaw is rated Important - a severity-sorted list would bury it.

Patch this week

Publicly disclosed

Details are already public. Working exploits typically follow within days.

Nothing was disclosed before the patch shipped.

The numbers

What’s in this release

Where the 89 entries actually come from

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

74 Microsoft products14 Azure Linux (Mariner)1 Edge (Chromium)

Severity

Microsoft channel only · 74 CVEs

April 2019 severity breakdown
Critical17
Important57
Moderate0
Low0

Impact type

What an attacker gains if it works

April 2019 impact breakdown
Remote Code Execution35
Elevation of Privilege12
Information Disclosure12
Spoofing12
Denial of Service1
Security Feature Bypass1
Tampering1

Most-affected components

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

Microsoft Windows18Microsoft Scripting Engine11Team Foundation Server9Microsoft Office8Microsoft JET Database Engine5Microsoft XML5Microsoft Graphics Component4Windows Kernel3Microsoft Exchange Server2Microsoft Office SharePoint2.NET Core1Adobe Flash Player1
Every patch

Browse all 89 entries

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

Showing 74 of 74
74 Microsoft vulnerabilities in the April 2019 Patch Tuesday, sortable by severity, CVSS and exploit status.
TitleStatusKB
ImportantCVE-2019-0859Win32k Elevation of Privilege VulnerabilityEoP7.8ExploitedWindows Kernel4493441 +13
ImportantCVE-2019-0803Win32k Elevation of Privilege VulnerabilityEoP7.0ExploitedMicrosoft Graphics Component4493441 +13
CriticalCVE-2019-0793MS XML Remote Code Execution VulnerabilityRCE7.8More likelyMicrosoft XML4493441 +13
CriticalCVE-2019-0753Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4493435 +9
CriticalCVE-2019-0739Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +5
CriticalCVE-2019-0806Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +5
CriticalCVE-2019-0810Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +5
CriticalCVE-2019-0812Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +5
CriticalCVE-2019-0829Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +4
CriticalCVE-2019-0860Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +6
CriticalCVE-2019-0861Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4493441 +5
ImportantCVE-2019-0685Win32k Elevation of Privilege VulnerabilityEoP7.8More likelyMicrosoft Windows4493441 +4
ImportantCVE-2019-0794OLE Automation Remote Code Execution VulnerabilityRCE7.8More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0752Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4493435 +9
ImportantCVE-2019-0735Windows CSRSS Elevation of Privilege VulnerabilityEoP7.0More likelyCSRSS4493441 +13
ImportantCVE-2019-0836Windows Elevation of Privilege VulnerabilityEoP7.0More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0731Windows Elevation of Privilege VulnerabilityEoP6.8More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0730Windows Elevation of Privilege VulnerabilityEoP6.7More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0805Windows Elevation of Privilege VulnerabilityEoP6.7More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0796Windows Elevation of Privilege VulnerabilityEoP6.3More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0840Windows Kernel Information Disclosure VulnerabilityInfo Disc.5.5More likelyMicrosoft Windows4493441 +2
ImportantCVE-2019-0844Windows Kernel Information Disclosure VulnerabilityInfo Disc.5.5More likelyWindows Kernel4493441 +13
ImportantCVE-2019-0732Windows Security Feature Bypass VulnerabilityBypass5.3More likelyMicrosoft Windows4493441 +13
ImportantCVE-2019-0814Win32k Information Disclosure VulnerabilityInfo Disc.4.7More likelyMicrosoft Windows4493441 +4
ImportantCVE-2019-0801Office Remote Code Execution VulnerabilityRCE-More likelyMicrosoft Office4462223 +2
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 35 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 74 vulnerabilities in April 2019, across Windows, Browser, Developer Tools and Microsoft Office. 17 are rated Critical, 0 were publicly disclosed before the patch shipped, and 2 were already being exploited. Note that Microsoft's release document lists 89 entries in total, but 14 of those are Azure Linux package updates and 1 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 1 Edge entries alongside Microsoft product fixes would inflate the headline number and imply work for your Windows Update rings that does not exist.