PatchTheCVECVE-2026-50343: Improper privilege management in Microsoft Install Service allows an authorized attacker to elevate privileges
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Routine
HIGH 7.8WATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2026-50343 is a high-severity flaw (CVSS 7.8) affecting windows 10 1809, windows 10 21h2, windows 10 22h2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Improper privilege management in Microsoft Install Service allows an authorized attacker to elevate privileges locally.
Why this priority
- High severity
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.8 (High) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 78%) |
| CISA exploited list | No |
| Weakness | CWE-269 |
| Published | 2026-07-14 |
| Last modified | 2026-07-22 |
Publisher (CNA): Microsoft Corporation · Vendor: microsoft
Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
microsoft windows 10 1809 UPGRADE
Affected: < 10.0.17763.9020
Fixed in: 10.0.17763.9020
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 10 21h2 UPGRADE
Affected: < 10.0.19044.7548
Fixed in: 10.0.19044.7548
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 10 22h2 UPGRADE
Affected: < 10.0.19045.7548
Fixed in: 10.0.19045.7548
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 11 24h2 UPGRADE
Affected: < 10.0.26100.8875
Fixed in: 10.0.26100.8875
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 11 25h2 UPGRADE
Affected: < 10.0.26200.8875
Fixed in: 10.0.26200.8875
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 11 26h1 UPGRADE
Affected: < 10.0.28000.2269 · < 10.0.28000.2525
Fixed in: 10.0.28000.2269, 10.0.28000.2525
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Advisories and coverage
Research and news
- Google Project Zero: Windows Exploitation Techniques: Dangling COM Object Registrations 2026-09-21
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-50343?
windows 10 1809: upgrade to 10.0.17763.9020; windows 10 21h2: upgrade to 10.0.19044.7548; windows 10 22h2: upgrade to 10.0.19045.7548. Exact commands for each OS are on this page.
Is CVE-2026-50343 being exploited?
CVE-2026-50343 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-50343 affect?
CVE-2026-50343 affects windows 10 1809, windows 10 21h2, windows 10 22h2. Severity is high (CVSS 7.8). Improper privilege management in Microsoft Install Service allows an authorized attacker to elevate privileges locally.
How urgent is CVE-2026-50343?
Priority 38/100. High severity; On your watchlist
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