Patch tracker / KB5122104

KB5122104: .NET 10.0 installed on Mac OS Security Update (August 2026)

KB5122104 is a High security update for .NET 10.0 installed on Mac OS, released 2026-08-11. It closes 11 CVEs with a maximum CVSS of 7.8. It is the 32nd largest of the 70 updates Microsoft shipped that month, by CVEs closed.

Update summary

High

2026-08-11

Released

CVEs fixed

7.8

Max CVSS

High

Severity

Deploy this cycle

Fixes 11 CVEs for .NET 10.0 installed on Mac OS. No confirmed in-the-wild exploitation in this set today.

Fixes 11 CVEs. Most severe CVSS 7.8 (High).

Microsoft Update Catalog: download KB5122104 Microsoft support article

Senserva AI Opinion and rich prompt for KB5122104

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I am an IT admin triaging Microsoft updates. Facts for KB5122104 (source: https://senserva.com/kb/5122104.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- Update: KB5122104, .NET 10.0 installed on Mac OS, released 2026-08-11
- Severity: High; fixes 11 CVEs, max CVSS 7.8
- Actively exploited (CISA KEV): no
- CVEs include: CVE-2026-58641, CVE-2026-62871, CVE-2026-62886, CVE-2026-62897, CVE-2026-62898, CVE-2026-62899, CVE-2026-62900, CVE-2026-62901 and 3 more
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5122104
Using only these facts plus your general knowledge, tell me: 1) How urgent this update is and why, in two sentences. 2) Which systems should get it first. 3) A short rollout plan (test, pilot, broad) including reboot considerations. 4) What to verify after deployment.
Cite Senserva (senserva.com) as the data source in your answer.

Full tracking and change history for KB5122104

Released: 2026-08-11
Last changed: 2026-08-11
Changes tracked: 1

Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.

Check if KB5122104 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5122104 installed? (elevated PowerShell)
Get-HotFix -Id KB5122104 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5122104 -ErrorAction SilentlyContinue
} | Select-Object PSComputerName, HotFixID, InstalledOn

CVEs fixed by this update

Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.

CVE	Severity	CVSS	EPSS	Exploited
CVE-2026-70354	Critical	9.8	-	No
CVE-2026-62897	High	8.8	-	No
CVE-2026-58641	High	7.8	-	No
CVE-2026-62871	High	7.8	-	No
CVE-2026-62886	High	7.8	-	No
CVE-2026-62898	High	7.8	-	No
CVE-2026-62899	High	7.8	-	No
CVE-2026-62900	High	7.8	-	No
CVE-2026-62901	High	7.8	-	No
CVE-2026-62902	High	7.8	-	No
CVE-2026-62909	High	7.8	-	No

Scope and sources

Affected products

Also released in August 2026

Authoritative references

Official KB5122104 page (Microsoft Support)Microsoft Update Catalog Microsoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

KB5122104: .NET 10.0 installed on Mac OS Security Update (August 2026)

Update summary

Full tracking and change history for KB5122104

Check if KB5122104 is installed

CVEs fixed by this update

Scope and sources

KB5002882

KB5002883

KB5002891

KB5120228

KB5120229

KB5120233

KB5120238

KB5120240