Trinetri logo
Updated monthly

Microsoft Patch Tuesday
May 2018

Microsoft's May 2018 Patch Tuesday fixes 68 vulnerabilities across Windows, Browser and Microsoft Office - 23 rated Critical, 3 publicly disclosed before the patch shipped, 2 already exploited in the wild. Patch CVE-2018-8174 first.

Released May 8, 2018, 10:00 PT2 actively exploited3 publicly disclosed85 KB articles to deploy

May 2018 Patch Tuesday at a glance

68
Microsoft CVEs
excl. Edge & Azure Linux
23
Critical
34% of the release
2
Actively exploited
CVE-2018-8174
3
Publicly disclosed
known before the patch
7.6
Highest CVSS
CVE-2018-0959
85
KB articles
what you actually deploy

Why this number differs from other roundups. Microsoft's May 2018 release document lists 76 entries. 4 are Azure Linux (Mariner) OS package updates and 4 are republished Chromium fixes for Edge - neither is a Microsoft product vulnerability. The 68 above is the real Patch Tuesday set. See the breakdown →

The numbers

What’s in this release

Where the 76 entries actually come from

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

68 Microsoft products4 Azure Linux (Mariner)4 Edge (Chromium)

Severity

Microsoft channel only · 68 CVEs

May 2018 severity breakdown
Critical23
Important43
Moderate0
Low2

Impact type

What an attacker gains if it works

May 2018 impact breakdown
Remote Code Execution32
Elevation of Privilege16
Security Feature Bypass9
Information Disclosure8
Spoofing2
Denial of Service1

Most-affected components

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

Microsoft Scripting Engine17Microsoft Office15Microsoft Exchange Server5Microsoft Windows5Windows Kernel5Microsoft Graphics Component4Device Guard3.NET Framework2Microsoft Browsers2Windows Hyper-V2Adobe Flash Player1Azure1
Every patch

Browse all 76 entries

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

Showing 68 of 68
68 Microsoft vulnerabilities in the May 2018 Patch Tuesday, sortable by severity, CVSS and exploit status.
TitleStatusKB
CriticalCVE-2018-8174Windows VBScript Engine Remote Code Execution VulnerabilityRCE7.5ExploitedMicrosoft Windows4103712 +11
ImportantCVE-2018-8120Win32k Elevation of Privilege VulnerabilityEoP7.0ExploitedMicrosoft Graphics Component4103712 +2
ImportantCVE-2018-8170Windows Image Elevation of Privilege VulnerabilityEoP7.0DisclosedMore likelyMicrosoft Windows4103727 +1
ImportantCVE-2018-8176Microsoft PowerPoint Remote Code Execution VulnerabilityRCE-DisclosedMicrosoft Office—
ImportantCVE-2018-8141Windows Kernel Information Disclosure VulnerabilityInfo Disc.4.7DisclosedWindows Kernel4103727
CriticalCVE-2018-0955Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4103716 +8
CriticalCVE-2018-1022Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4103716 +7
CriticalCVE-2018-8114Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4103716 +7
CriticalCVE-2018-8122Scripting Engine Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Scripting Engine4103716 +7
CriticalCVE-2018-8178Microsoft Browser Memory Corruption VulnerabilityRCE7.5More likelyMicrosoft Browsers4103716 +7
CriticalCVE-2018-0943Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103716 +4
CriticalCVE-2018-0945Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103721
CriticalCVE-2018-0946Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103721 +2
CriticalCVE-2018-0951Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103723 +2
CriticalCVE-2018-0953Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103716 +4
CriticalCVE-2018-0954Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103716 +8
CriticalCVE-2018-8128Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103721 +2
CriticalCVE-2018-8130Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103721 +1
CriticalCVE-2018-8133Chakra Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103716 +4
CriticalCVE-2018-8137Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103716 +4
CriticalCVE-2018-8139Scripting Engine Memory Corruption VulnerabilityRCE4.2More likelyMicrosoft Scripting Engine4103721
ImportantCVE-2018-8124Win32k Elevation of Privilege VulnerabilityEoP7.0More likelyMicrosoft Graphics Component4103712 +12
ImportantCVE-2018-8134Windows Elevation of Privilege VulnerabilityEoP7.0More likelyWindows Kernel4103715 +6
ImportantCVE-2018-8164Win32k Elevation of Privilege VulnerabilityEoP7.0More likelyMicrosoft Graphics Component4103712 +11
ImportantCVE-2018-8165DirectX Graphics Kernel Elevation of Privilege VulnerabilityEoP7.0More likelyMicrosoft Graphics Component4103716 +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 85 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
Stop the sprawl. Eliminate the guesswork.

Ready to See Autonomous Endpoint Management in Action?

Experience how Trinetri transforms endpoint chaos into clarity. Try the 30 minute demo session, our experts will walk you through how AI-powered automation, real-time visibility, and unified control can secure your entire hybrid environment, without the overhead.

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 68 vulnerabilities in May 2018, across Windows, Browser, Microsoft Office and Developer Tools. 23 are rated Critical, 3 were publicly disclosed before the patch shipped, and 2 were already being exploited. Note that Microsoft's release document lists 76 entries in total, but 4 of those are Azure Linux package updates and 4 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 4 Edge entries alongside Microsoft product fixes would inflate the headline number and imply work for your Windows Update rings that does not exist.