Patch tracker / KB5121000

KB5121000: Windows Server 2022 Security Update (August 2026)

KB5121000 is a Critical security update for Windows Server 2022, released 2026-08-11. It closes 195 CVEs with a maximum CVSS of 9.8. At least one of them is actively exploited (CISA KEV), so this is a deploy-first update. The most likely of them to be attacked is CVE-2026-42976, which FIRST.org rates at 54% probability of exploitation in the next 30 days.

Update summary

CriticalCISA KEV
2026-08-11
Released
195
CVEs fixed
9.8
Max CVSS v3
Critical
Severity
Deploy now
This update fixes vulnerabilities confirmed exploited in the wild.

Fixes 195 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 6.2%. Among the top half of tracked Microsoft updates by EPSS exploit probability.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for Windows 10 Version 1809 for x64-based Systems has shipped since this one: KB5122871 (2026-09-08). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.

Senserva found thisread these before you deploy broadly

Microsoft documents 1 known issue with this update.

  • Microsoft Teams and Outlook might fail to launch on ARM-based devices

The full text, quoted from Microsoft

Microsoft Update Catalog: download KB5121000Microsoft support article
Senserva AI Opinion and rich prompt for KB5121000

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

Full tracking and change history for KB5121000

Released
2026-08-11
Last changed
2026-09-15
Changes tracked
8

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.

Senserva Watchevery change we have recorded for this one
What changed, and when

The strongest signal is the steady upward trend in fixes for KB5121000. On 2026-08-12 the count moved from 196 to 197, then on 2026-08-20 it rose again from 197 to 198. This incremental climb means the update remains actively maintained, so IT admins should confirm they have the latest revision deployed today.

  • 2026-08-12 CVEs fixed 196 to 197
  • 2026-08-20 CVEs fixed 197 to 198

Recorded by Senserva on the dates shown, from the MSRC release feed. This is what moved and when, which neither the vendor advisory nor NVD publishes.

Check if KB5121000 is installed

Elevated PowerShell. No output means it is not installed.

Known issues, from Microsoft

Quoted from Microsoft's support article for KB5121000 (checked 2026-09-18). Verify against the article before acting.

Microsoft Teams and Outlook might fail to launch on ARM-based devices

Symptoms

After installing Windows security updates released on or after August 11, 2026, (KB5121000) , Microsoft Teams and the new Outlook for Windows might fail to launch or might close unexpectedly on ARM-based devices, such as Surface Pro 11 and Surface Laptop 7. Classic Outlook, Word, Excel, and other applications are not known to be affected. This issue is most likely to occur on new or freshly imaged PCs that have not yet installed any Microsoft Store updates.

Workaround

To work around this issue:

Open Microsoft Store.

Select Downloads > Check for updates.

Install the latest update for the Auto Super Resolution Package (version 1.0.19.0 or later).

Resolution

This issue is resolved in Windows updates released on and after September 8, 2026 such as KB5124012 . We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.

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.

CVESeverityCVSSEPSSExploited
CVE-2026-68820High7.06.2%KEV
CVE-2026-59128Critical9.86.2%No
CVE-2026-59130Critical9.86.2%No
CVE-2026-59131Critical9.86.2%No
CVE-2026-59135Critical9.86.2%No
CVE-2026-59136Critical9.86.2%No
CVE-2026-59137Critical9.86.2%No
CVE-2026-61347Critical9.86.2%No
CVE-2026-61350Critical9.86.2%No
CVE-2026-61360Critical9.86.2%No
CVE-2026-61368Critical9.86.2%No
CVE-2026-61928Critical9.86.2%No
CVE-2026-61933Critical9.86.2%No
CVE-2026-61936Critical9.86.2%No
CVE-2026-62703Critical9.86.2%No
CVE-2026-62709Critical9.86.2%No
CVE-2026-62730Critical9.86.2%No
CVE-2026-62738Critical9.86.2%No
CVE-2026-62740Critical9.86.2%No
CVE-2026-62743Critical9.86.2%No
CVE-2026-62746Critical9.86.2%No
CVE-2026-62757Critical9.86.2%No
CVE-2026-62775Critical9.86.2%No
CVE-2026-62786Critical9.86.2%No
CVE-2026-62793Critical9.86.2%No
CVE-2026-62796Critical9.86.2%No
CVE-2026-62798Critical9.86.2%No
CVE-2026-62815Critical9.86.2%No
CVE-2026-62887Critical9.86.2%No
CVE-2026-65662Critical9.86.2%No
CVE-2026-65777Critical9.86.2%No
CVE-2026-65784Critical9.86.2%No
CVE-2026-6727Critical9.86.2%No
CVE-2026-70348Critical9.86.2%No
CVE-2026-72971Critical9.86.2%No
CVE-2026-49179High8.86.2%No
CVE-2026-62784High8.86.2%No
CVE-2026-62785High8.86.2%No
CVE-2026-62790High8.86.2%No
CVE-2026-62795High8.86.2%No
CVE-2026-62800High8.86.2%No
CVE-2026-62816High8.86.2%No
CVE-2026-62822High8.86.2%No
CVE-2026-56179High8.36.2%No
CVE-2026-62781High8.16.2%No
CVE-2026-62792High8.16.2%No
CVE-2026-62819High8.16.2%No
CVE-2026-62889High8.16.2%No
CVE-2026-66802High8.16.2%No
CVE-2026-6726High7.96.2%No
CVE-2026-42976High7.854%No
CVE-2026-54984High7.86.2%No
CVE-2026-59127High7.86.2%No
CVE-2026-61349High7.86.2%No
CVE-2026-61353High7.86.2%No
CVE-2026-61355High7.86.2%No
CVE-2026-61356High7.86.2%No
CVE-2026-61357High7.86.2%No
CVE-2026-61358High7.86.2%No
CVE-2026-61359High7.86.2%No
CVE-2026-61364High7.86.2%No
CVE-2026-61365High7.86.2%No
CVE-2026-61367High7.86.2%No
CVE-2026-61923High7.86.2%No
CVE-2026-61925High7.86.2%No
CVE-2026-61926High7.86.2%No
CVE-2026-61930High7.86.2%No
CVE-2026-61934High7.86.2%No
CVE-2026-61937High7.86.2%No
CVE-2026-62688High7.86.2%No
CVE-2026-62692High7.86.2%No
CVE-2026-62695High7.86.2%No
CVE-2026-62696High7.86.2%No
CVE-2026-62698High7.86.2%No
CVE-2026-62700High7.86.2%No
CVE-2026-62701High7.86.2%No
CVE-2026-62707High7.86.2%No
CVE-2026-62710High7.86.2%No
CVE-2026-62711High7.86.2%No
CVE-2026-62712High7.86.2%No
CVE-2026-62713High7.86.2%No
CVE-2026-62717High7.86.2%No
CVE-2026-62719High7.86.2%No
CVE-2026-62722High7.86.2%No
CVE-2026-62732High7.86.2%No
CVE-2026-62733High7.86.2%No
CVE-2026-62735High7.86.2%No
CVE-2026-62736High7.86.2%No
CVE-2026-62737High7.86.2%No
CVE-2026-62739High7.86.2%No
CVE-2026-62741High7.86.2%No
CVE-2026-62747High7.86.2%No
CVE-2026-62751High7.86.2%No
CVE-2026-62752High7.86.2%No
CVE-2026-62754High7.86.2%No
CVE-2026-62755High7.86.2%No
CVE-2026-62758High7.86.2%No
CVE-2026-62768High7.86.2%No
CVE-2026-62770High7.86.2%No
CVE-2026-62771High7.86.2%No
CVE-2026-62772High7.86.2%No
CVE-2026-62777High7.86.2%No
CVE-2026-62779High7.86.2%No
CVE-2026-62783High7.86.2%No
CVE-2026-62797High7.86.2%No
CVE-2026-62799High7.86.2%No
CVE-2026-62811High7.86.2%No
CVE-2026-62832High7.86.2%No
CVE-2026-62876High7.86.2%No
CVE-2026-62877High7.86.2%No
CVE-2026-62880High7.86.2%No
CVE-2026-62885High7.86.2%No
CVE-2026-62888High7.86.2%No
CVE-2026-62890High7.86.2%No
CVE-2026-62894High7.86.2%No
CVE-2026-65671High7.86.2%No
CVE-2026-65672High7.86.2%No
CVE-2026-65773High7.86.2%No
CVE-2026-65774High7.86.2%No
CVE-2026-65775High7.86.2%No
CVE-2026-65786High7.86.2%No
CVE-2026-65787High7.86.2%No
CVE-2026-65790High7.86.2%No
CVE-2026-65814High7.86.2%No
CVE-2026-66799High7.86.2%No
CVE-2026-66804High7.86.2%No
CVE-2026-70344High7.86.2%No
CVE-2026-70345High7.86.2%No
CVE-2026-70346High7.86.2%No
CVE-2026-70347High7.86.2%No
CVE-2026-54113High7.56.2%No
CVE-2026-59132High7.56.2%No
CVE-2026-59134High7.56.2%No
CVE-2026-61352High7.56.2%No
CVE-2026-61363High7.56.2%No
CVE-2026-50472High7.06.2%No
CVE-2026-59122High7.06.2%No
CVE-2026-59125High7.06.2%No
CVE-2026-59126High7.06.2%No
CVE-2026-61346High7.06.2%No
CVE-2026-61348High7.06.2%No
CVE-2026-61361High7.06.2%No
CVE-2026-61366High7.06.2%No
CVE-2026-61927High7.06.2%No
CVE-2026-61929High7.06.2%No
CVE-2026-61938High7.06.2%No
CVE-2026-61939High7.06.2%No
CVE-2026-62690High7.06.2%No
CVE-2026-62693High7.06.2%No
CVE-2026-62705High7.06.2%No
CVE-2026-62723High7.06.2%No
CVE-2026-62724High7.06.2%No
CVE-2026-62725High7.06.2%No
CVE-2026-62726High7.06.2%No
CVE-2026-62727High7.06.2%No
CVE-2026-62728High7.06.2%No
CVE-2026-62729High7.06.2%No
CVE-2026-62734High7.06.2%No
CVE-2026-62748High7.06.2%No
CVE-2026-62749High7.06.2%No
CVE-2026-62753High7.06.2%No
CVE-2026-62766High7.06.2%No
CVE-2026-62773High7.06.2%No
CVE-2026-62774High7.06.2%No
CVE-2026-62780High7.06.2%No
CVE-2026-62788High7.06.2%No
CVE-2026-62892High7.06.2%No
CVE-2026-62908High7.06.2%No
CVE-2026-65678High7.06.2%No
CVE-2026-65776High7.06.2%No
CVE-2026-65779High7.06.2%No
CVE-2026-65780High7.06.2%No
CVE-2026-65788High7.06.2%No
CVE-2026-70307High7.06.2%No
CVE-2026-62699Medium6.86.2%No
CVE-2026-62702Medium6.86.2%No
CVE-2026-62769Medium6.76.2%No
CVE-2026-62881Medium6.76.2%No
CVE-2026-62883Medium6.76.2%No
CVE-2026-65795Medium6.76.2%No
CVE-2026-65797Medium6.76.2%No
CVE-2026-65798Medium6.76.2%No
CVE-2026-65799Medium6.76.2%No
CVE-2026-70304Medium6.76.2%No
CVE-2026-70330Medium6.76.2%No
CVE-2026-59138Medium6.56.2%No
CVE-2026-61345Medium6.56.2%No
CVE-2026-61918Medium6.56.2%No
CVE-2026-61921Medium6.56.2%No
CVE-2026-61924Medium6.56.2%No
CVE-2026-62750Medium6.56.2%No
CVE-2026-62782Medium6.56.2%No
CVE-2026-65785Medium6.56.2%No
CVE-2026-65794Medium6.56.2%No
CVE-2026-62708Medium6.46.2%No

Scope and sources

Affected products
Also released in August 2026

KB5002882

39 CVEs · Critical · exploited

KB5002883

40 CVEs · Critical · exploited

KB5002891

40 CVEs · Critical · exploited

KB5120228

215 CVEs · Critical · exploited

KB5120229

195 CVEs · Critical · exploited

KB5120233

215 CVEs · Critical · exploited

KB5120238

183 CVEs · Critical · exploited

KB5120240

170 CVEs · Critical · exploited

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5121000 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

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

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
All information provided as is, without warranty; verify against the vendor advisory before acting. All information and usage is subject to the Senserva EULA. Data notice and terms.