Windows · Microsoft · released September 8, 2026
Windows security updates, September 2026: every vulnerability, rated
Microsoft published 705 Windows vulnerabilities in September 2026, most of them on Patch Tuesday, September 8, 2026. 71 are rated Critical. 1 was already being exploited, so it goes to the top of the list. 119 more deserve attention this week; 585 can follow the normal monthly rollout. 27 were fixed by an earlier update and only disclosed this month, so a PC that is already current is covered. The updates that carry these fixes need a restart.
- CVEs
- 705
- Patch now
- 1
- This week
- 119
- Normal cycle
- 543
- Low
- 42
Fixed in: September 2026 Windows security update restart requiredMicrosoft release notes
Page 12 of 12 · sorted by risk, then score
Normal cycle3 on this page · tap one for its risk review
- Normal cycleWindowsSeptember 8, 2026
CVE-2026-69713Windows Secure Boot
Security Feature Bypass · Severity Important · CVSS 4.4
In Windows Secure Boot, an attacker who already has admin rights could get around a Windows security protection once they can run code on the PC. Microsoft severity Important, CVSS 4.4. Microsoft rates it "exploitation less likely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- Normal cycleWindowsSeptember 8, 2026
CVE-2026-73019Windows URL Moniker
Security Feature Bypass · Severity Important · CVSS 4.3
In Windows URL Moniker, an attacker with no account could get around a Windows security protection over the network, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 4.3. Microsoft rates it "exploitation less likely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- Normal cycleWindowsSeptember 8, 2026
CVE-2026-78455Xbox
Information Disclosure · Severity Important · CVSS 4.3
In Xbox, an attacker with no account could read information they shouldn't see with physical access to the device, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 4.3. Microsoft rates it "exploitation less likely". Fixed in the September 2026 Windows security update (KB5122876, KB5122878, KB5122880) for 22 supported Windows versions; a restart is required.
Low42 on this page · tap one for its risk review
- LowWindowsSeptember 8, 2026
CVE-2026-69803Windows DHCP Server
Information Disclosure · Severity Important · CVSS 5.9
In Windows DHCP Server, an attacker with no account could read information they shouldn't see over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69929Windows DHCP Server
Information Disclosure · Severity Important · CVSS 5.9
In Windows DHCP Server, an attacker with no account could read information they shouldn't see over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69930Windows DHCP Server
Information Disclosure · Severity Important · CVSS 5.9
In Windows DHCP Server, an attacker with no account could read information they shouldn't see over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-70091Windows DNS
Denial of Service · Severity Important · CVSS 5.9
In Windows DNS, an attacker with no account could crash or stall the affected service over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-70124Windows DHCP Server
Information Disclosure · Severity Important · CVSS 5.9
In Windows DHCP Server, an attacker with no account could read information they shouldn't see over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-72978Active Directory Federation Services (AD FS)
Denial of Service · Severity Important · CVSS 5.9
In Active Directory Federation Services (AD FS), an attacker with no account could crash or stall the affected service over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-78523Windows DNS Server
Denial of Service · Severity Important · CVSS 5.9
In Windows DNS Server, an attacker with no account could crash or stall the affected service over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.9. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 11, 2026
CVE-2026-69405Windows DHCP Server
Denial of Service · Severity Important · CVSS 5.7 · Out of band
In Windows DHCP Server, an attacker with an ordinary user account could crash or stall the affected service from the same local network without anyone clicking anything. Microsoft severity Important, CVSS 5.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69416Windows DHCP Server
Denial of Service · Severity Important · CVSS 5.7
In Windows DHCP Server, an attacker with an ordinary user account could crash or stall the affected service from the same local network without anyone clicking anything. Microsoft severity Important, CVSS 5.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69507Microsoft Windows Search Component
Information Disclosure · Severity Important · CVSS 5.7
In Microsoft Windows Search Component, an attacker with an ordinary user account could read information they shouldn't see over the network, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 5.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122880, KB5122882) for 12 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69572Windows SMB Client
Information Disclosure · Severity Important · CVSS 5.7
In Windows SMB Client, an attacker with an ordinary user account could read information they shouldn't see over the network, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 5.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69591Windows NTFS
Information Disclosure · Severity Important · CVSS 5.7
In Windows NTFS, an attacker with an ordinary user account could read information they shouldn't see over the network, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 5.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 22 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-57085Windows Print Spooler
Information Disclosure · Severity Important · CVSS 5.5 · Fixed earlier (July 2026)
In Windows Print Spooler, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Microsoft disclosed it on September 8, 2026, but the fix had already shipped in the July 2026 Windows security update (KB5099444, KB5099445, KB5099535) for 27 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-68842Windows MIDI Service Module
Information Disclosure · Severity Important · CVSS 5.5
In Windows MIDI Service Module, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5124008, KB5124012) for 6 supported Windows versions; a restart is required.
- LowWindowsSeptember 30, 2026
CVE-2026-69288Windows GDI+
Information Disclosure · Severity Important · CVSS 5.5 · Out of band
In Windows GDI+, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69318Windows Imaging Component
Information Disclosure · Severity Important · CVSS 5.5
In Windows Imaging Component, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69343Windows Overlay Filter
Information Disclosure · Severity Important · CVSS 5.5
In Windows Overlay Filter, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 28 supported Windows versions; a restart is required.
- LowWindowsSeptember 30, 2026
CVE-2026-69504Windows NTFS
Information Disclosure · Severity Important · CVSS 5.5 · Out of band
In Windows NTFS, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69527Windows USB Mass Storage Class Driver
Information Disclosure · Severity Important · CVSS 5.5
In Windows USB Mass Storage Class Driver, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69568Storage Spaces Controller
Information Disclosure · Severity Important · CVSS 5.5
In Storage Spaces Controller, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69609Win32k
Information Disclosure · Severity Important · CVSS 5.5
In Win32k, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69616Windows Remote Desktop Services
Information Disclosure · Severity Important · CVSS 5.5
In Windows Remote Desktop Services, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69618Windows SMB Client
Information Disclosure · Severity Important · CVSS 5.5
In Windows SMB Client, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69627Windows Remote Desktop Licensing Service
Information Disclosure · Severity Important · CVSS 5.5
In Windows Remote Desktop Licensing Service, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69672Windows DNS
Information Disclosure · Severity Important · CVSS 5.5
In Windows DNS, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122882) for 16 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69684Windows Error Reporting
Information Disclosure · Severity Important · CVSS 5.5
In Windows Error Reporting, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 28 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69741Windows Spaceport.sys
Information Disclosure · Severity Important · CVSS 5.5
In Windows Spaceport.sys, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122878, KB5122880) for 18 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69770Windows Spaceport.sys
Information Disclosure · Severity Important · CVSS 5.5
In Windows Spaceport.sys, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 28 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69794Windows Encrypting File System (EFS)
Information Disclosure · Severity Important · CVSS 5.5
In Windows Encrypting File System (EFS), an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 26 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69808Win32k
Information Disclosure · Severity Important · CVSS 5.5
In Win32k, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69862Windows Wireless Wide Area Network Service
Information Disclosure · Severity Important · CVSS 5.5
In Windows Wireless Wide Area Network Service, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122876, KB5122878, KB5122880) for 22 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-72945Windows Task Scheduler
Information Disclosure · Severity Important · CVSS 5.5
In Windows Task Scheduler, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122876, KB5122878, KB5122880) for 18 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-73008Windows Biometric Service
Information Disclosure · Severity Important · CVSS 5.5
In Windows Biometric Service, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 5.5. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 26 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-70575Windows Schannel
Denial of Service · Severity Important · CVSS 5.3
In Windows Schannel, an attacker with an ordinary user account could crash or stall the affected service over the network without anyone clicking anything. Microsoft severity Important, CVSS 5.3. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122880, KB5122882) for 12 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69474Windows Overlay Filter
Information Disclosure · Severity Important · CVSS 4.8
In Windows Overlay Filter, an attacker with an ordinary user account could read information they shouldn't see over the network, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 4.8. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 28 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69316Windows Overlay Filter
Information Disclosure · Severity Important · CVSS 4.7
In Windows Overlay Filter, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 4.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 26 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69483Windows Image Acquisition
Information Disclosure · Severity Important · CVSS 4.7
In Windows Image Acquisition, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 4.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69853Win32k
Information Disclosure · Severity Important · CVSS 4.7
In Win32k, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 4.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69895Windows Spaceport.sys
Information Disclosure · Severity Important · CVSS 4.7
In Windows Spaceport.sys, an attacker with an ordinary user account could read information they shouldn't see once they can run code on the PC. Microsoft severity Important, CVSS 4.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-72931Windows Secure Socket Tunneling Protocol (SSTP)
Denial of Service · Severity Important · CVSS 4.7
In Windows Secure Socket Tunneling Protocol (SSTP), an attacker with an ordinary user account could crash or stall the affected service once they can run code on the PC. Microsoft severity Important, CVSS 4.7. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-69381Windows Storage Port Driver
Information Disclosure · Severity Important · CVSS 4.6
In Windows Storage Port Driver, an attacker with no account could read information they shouldn't see with physical access to the device. Microsoft severity Important, CVSS 4.6. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
- LowWindowsSeptember 8, 2026
CVE-2026-78516Windows Storage
Information Disclosure · Severity Important · CVSS 4.3
In Windows Storage, an attacker with no account could read information they shouldn't see with physical access to the device, but only if someone opens a file, link or message. Microsoft severity Important, CVSS 4.3. Microsoft rates it "exploitation unlikely". Fixed in the September 2026 Windows security update (KB5122871, KB5122876, KB5122878) for 30 supported Windows versions; a restart is required.
Why an MSP manages this
Reading the list is the easy part
Nobody running a business reads all of them, and nobody should have to. The work is deciding which ones matter today, testing the fixes, getting them onto every PC and Mac without breaking the workday, and proving it was done.
- 01
Triage that starts with the exploited ones
Most of these fixes can ride the normal monthly rollout. A handful need action the same day. Telling them apart, every month, on every machine, is the core of the work, and it is the part an office manager rarely has time for.
- 02
Testing before everyone gets it
Updates go to a test ring and a pilot group first, so a broken accounting package or design tool shows up on two machines instead of forty, and the rollout pauses until it is sorted.
- 03
Restarts that don't wreck the workday
Windows updates usually need a restart and macOS updates often do. Deadlines, maintenance windows and grace periods get the fix installed without forcing a reboot in the middle of a client call.
- 04
Macs managed as seriously as PCs
Windows patching tools don't patch Macs. macOS updates need their own install-by deadlines through device management, and major upgrades need the same compatibility testing a Windows feature update gets.
- 05
A plan for machines that can't update
Hardware that ages out and versions past end of support stop getting every fix. They need a decision, isolate, upgrade or replace, before they become the easiest way in.
- 06
Proof when someone asks
Cyber insurance applications, customer security questionnaires and frameworks such as the FTC Safeguards Rule all ask how you keep systems patched. A managed service keeps the inventory and the reports that answer them.
The ins and outs
What keeping Windows and Mac patched actually involves
Windows
Patch Tuesday, and the exceptions
Microsoft ships security updates on the second Tuesday of each month, and out of band when something can't wait. This log marks the out-of-band ones.
Cumulative updates
Each month's Windows update carries the earlier months' fixes, so a PC that missed one catches up with the next, as long as it actually installs.
Fixed first, announced later
Some fixes ship before the vulnerability is disclosed. This log flags them, because a PC that is already current is already covered.
Rings, deferrals and deadlines
Windows Update for Business and Intune let you delay updates for a test group, set an install-by deadline and give a grace period before a forced restart.
Known Issue Rollback and safeguard holds
Microsoft can quietly roll back a change that breaks something, and holds back feature updates from PCs it knows will have trouble. Both explain why two PCs on the same network can be on different builds.
Feature updates and end of support
Each Windows version is serviced for a fixed period. Windows 10 PCs past end of support only get security fixes through the paid Extended Security Updates program.
Mac
No fixed release day
Apple publishes security updates when they are ready, often several times a month around a major release, so Mac patching runs on alerts, not a calendar.
Updates versus upgrades
A point update (26.7 to 26.7.1) fixes problems. A major upgrade (Tahoe to Golden Gate) changes the system and needs the same app testing as a Windows feature update.
Older versions get some fixes, not all
Apple's deployment guide says not every security issue is fixed in previous major versions. Staying a version behind is a choice with a cost, not a safe default.
Install-by deadlines through device management
Without enforcement, a macOS update prompt can be put off again and again. Device management can set a deadline so the update installs on schedule.
Macs that age out
When a Mac can no longer run a current macOS version, it stops getting the full set of fixes. Inventory by model and macOS version shows which ones are next.
Apple Business for zero-touch setup
New Macs enrolled through Apple Business arrive already managed, so update policy applies from the first login instead of after someone remembers to enroll them.
Both platforms
Third-party apps aren't on these lists
Browsers, PDF readers, accounting software, VPN clients and plug-ins patch on their own schedules. A machine can be current on Windows or macOS and still exposed through an app.
Firmware and drivers
BIOS and UEFI firmware, docks and network gear get security fixes too, and they rarely update themselves.
Recovery keys before big changes
Before a feature update or a major macOS upgrade, confirm BitLocker and FileVault recovery keys are escrowed somewhere you can reach.
Laptops that are rarely in the office
Remote and travelling staff need updates delivered over the internet with the same deadlines as office machines, or they drift months behind.
You can't patch what you can't see
An up-to-date inventory of every PC and Mac, with its version and last update, is what turns a list like this one into a finished job.