IT SBIT Services
Schneeberger
DEEN
Patch Tuesday

Patch Tuesday May 2026 – known issues, zero-days and what to do

On 12 May 2026 Microsoft fixed 162 vulnerabilities – critical: 46, already exploited (zero-days): 3. Known issues with the updates: none known.

162vulnerabilities
46critical
3zero-days
0known issues

What to do now

  • Zero-days first: 3 vulnerabilities are already being exploited (CVE-2026-42897, CVE-2026-41091, CVE-2026-45498) – install the updates as soon as possible, starting with servers and exposed systems.
  • 46 critical vulnerabilities (mainly Windows, Microsoft Office, Azure) – roll out promptly after a short test.
  • No issues are known so far with the updates of this month – test and roll out as usual.

Zero-days: already exploited

Critical vulnerabilities (45)

Show 39 more critical vulnerabilities

Updates (KB) of this month

KB numbers according to the Security Update Guide; known issues from our update issues – click a KB to see all its entries.

UpdateProduct familyVulnerabilitiesKnown issues
KB5087539Windows64none known
KB5087545Windows56none known
KB5087424Windows55none known
KB5087538Windows54none known
KB5087544Windows53none known
KB5094127Windows53none known
KB5087423Windows13none known
KB5002868Microsoft Office9none known
KB5002870Microsoft Office9none known
KB5002863Microsoft Office9none known
KB5002858Microsoft Office6none known
KB5089549Windows6none known
Show 38 more updates
UpdateProduct familyVulnerabilitiesKnown issues
KB5089466Windows6none known
KB5089548Windows5none known
KB5093446Developer tools (.NET, Visual Studio …)4none known
KB5093447Developer tools (.NET, Visual Studio …)4none known
KB5093448Developer tools (.NET, Visual Studio …)4none known
KB5087541Windows3none known
KB5002871Microsoft Office3none known
KB5002865Microsoft Office3none known
KB5002866Microsoft Office2none known
KB5087420Windows2none known
KB5093998Windows2none known
KB5078943Microsoft Dynamics2none known
KB5087065Developer tools (.NET, Visual Studio …)2none known
KB5087067Developer tools (.NET, Visual Studio …)2none known
KB5002869Microsoft Office1none known
KB5002872Microsoft Office1none known
KB5094144Windows ESU (Extended Security Updates)1none known
KB5094142Windows ESU (Extended Security Updates)1none known
KB5094140Windows ESU (Extended Security Updates)1none known
KB5094139Windows ESU (Extended Security Updates)1none known
KB5087069Developer tools (.NET, Visual Studio …)1none known
KB5087063Developer tools (.NET, Visual Studio …)1none known
KB5089899SQL Server1none known
KB5089900SQL Server1none known
KB5090347SQL Server1none known
KB5090408SQL Server1none known
KB5089271SQL Server1none known
KB5089270SQL Server1none known
KB5093780Microsoft Dynamics1none known
KB5086069Microsoft Dynamics1none known
KB5086070Microsoft Dynamics1none known
KB5086068Microsoft Dynamics1none known
KB5087537Windows1none known
KB5087471Windows1none known
KB5078737Windows1none known
KB5094125Windows1none known
KB5094126Windows1none known
KB5095051Windows1none known

Known issues with the updates

No issues are known so far with the updates of this month.

By product family

  • Windows67
  • Microsoft Office30
  • Azure26
  • Developer tools (.NET, Visual Studio …)11
  • Browser (Edge)9
  • Apps7
  • Microsoft Dynamics6
  • System Center and Defender3

More about this month

Where the information comes from

Fixed vulnerabilities, severity, zero-days and KB numbers come from the official Microsoft Security Update Guide (MSRC); known issues, workarounds and dated changes from our update issues, each with its source. “What to do now” is derived from this data using fixed rules, without AI.

Affected? We can help.

We check whether your systems are affected, apply workarounds properly and plan for dated changes in good time.

Get in touchAll known issues after updates