Patch tracker / KB5081278

KB5081278: Microsoft.Bcl.Memory 10.0 Security Update (March 2026)

KB5081278 is a High security update for Microsoft.Bcl.Memory 10.0, released 2026-03-10. It closes 2 CVEs with a maximum CVSS of 7.5. It is the 23rd largest of the 43 updates Microsoft shipped that month, by CVEs closed.

Update summary

High

2026-03-10

Released

CVEs fixed

7.5

Max CVSS v3

High

Severity

Deploy this cycle

Fixes 2 CVEs for Microsoft.Bcl.Memory 10.0. No confirmed in-the-wild exploitation in this set today.

Fixes 2 CVEs. Most severe CVSS 7.5 (High). EPSS exploit probability up to 2.8%. Among the top half of tracked Microsoft updates by EPSS exploit probability.

Microsoft Update Catalog: download KB5081278 Microsoft support article

Senserva AI Opinion for KB5081278

KB5081278 patches two vulnerabilities (CVE-2026-26127 and CVE-2026-26130) in Microsoft.Bcl.Memory 10.0 and the .NET 10.0 runtime on both Windows and Mac OS. The cross-platform reach matters here: any developer machine or server running .NET 10.0 apps, regardless of OS, is in scope. Highest Severity is High at CVSS 7.5, but exploitation likelihood is low with EPSS at 3 percent and no CISA KEV or ransomware association.

Do this: Inventory your Windows and Mac hosts running .NET 10.0 and update the runtime and the Microsoft.Bcl.Memory 10.0 package to the patched build.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5081278

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 KB5081278 (source: https://senserva.com/kb/5081278.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- Update: KB5081278, Microsoft.Bcl.Memory 10.0, released 2026-03-10
- Severity: High; fixes 2 CVEs, max CVSS 7.5
- Actively exploited (CISA KEV): no
- CVEs include: CVE-2026-26127, CVE-2026-26130
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5081278
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 KB5081278

Released: 2026-03-10
Last changed: 2026-03-10
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 KB5081278 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5081278 installed? (elevated PowerShell)
Get-HotFix -Id KB5081278 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5081278 -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-2026-26127	High	7.5	2.8%	No
CVE-2026-26130	High	7.5	2.8%	No

Scope and sources

Affected products

Also released in March 2026

Authoritative references

Official KB5081278 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.

KB5081278: Microsoft.Bcl.Memory 10.0 Security Update (March 2026)

Update summary

Full tracking and change history for KB5081278

Check if KB5081278 is installed

CVEs fixed by this update

Scope and sources

KB5002843

KB5002845

KB5002850

KB5077464

KB5077465

KB5077466

KB5077468

KB5077469