CVE-2026-50391
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper privilege management in Windows Group Policy allows an authorized attacker to elevate privileges locally.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA Windows Group Policy privilege management flaw allows a local, authorized attacker with existing access to manipulate Group Policy settings or their application to elevate privileges to a higher permission level. The CVSS 7.8 with Local attack vector indicates this is a local privilege escalation (LPE) vulnerability requiring authenticated but limited access.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 10.0.14393.9339< 10.0.17763.9020< 10.0.19044.7548< 10.0.19045.7548< 10.0.26100.8875< 10.0.26200.8875< 10.0.28000.2269< 10.0.28000.2525all versions= r2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine Windows version and build numberOpen Command Prompt or PowerShell and run: winver OR systeminfo | findstr /B /C:"OS Name" /C:"OS Version" /C:"Build Number". Alternatively, press Win+R, type winver, and note the full version and build number displayed.Affected if The detected build number falls below any of these thresholds: 14393.9339 (Win10 1607), 17763.9020 (Win10 1809), 19044.7548 (Win10 21h2), 19045.7548 (Win10 22h2), 26100.8875 (Win11 24h2), 26200.8875 (Win11 25h2), 28000.2269 or 28000.2525 (Win11 26h1), OR if running Windows Server 2012 / R2 at any ve
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Confirm the system is domain-joinedOpen Command Prompt and run: echo %USERDOMAIN% OR in PowerShell run: Get-CimInstance -ClassName Win32_ComputerSystem | Select-Object -ExpandProperty Domain. A domain member indicates Group Policy is actively applied.Affected if The system is joined to a domain (shows a domain name rather than WORKGROUP), which means Group Policy settings can be manipulated.
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Review Group Policy software installation settingsOpen Group Policy Management Console (gpmc.msc) if available, navigate to Computer Configuration > Policies > Software Settings > Software Installation. Check for any deployed packages. Alternatively, check the registry key: HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer for any entries.Affected if Group Policy Software Installation policy is configured and deploying packages, as this feature can be exploited for privilege escalation.
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Check Group Policy script execution settingsOpen gpmc.msc and navigate to Computer Configuration > Windows Settings > Scripts (Startup/Shutdown) and User Configuration > Windows Settings > Scripts (Logon/Logoff). Also check: HKLM\SOFTWARE\Policies\Microsoft\Windows\System\Scripts for configured scripts.Affected if Startup/shutdown or logon/logoff scripts are configured via Group Policy, as these can be manipulated to execute privileged operations.
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Inspect Group Policy preferences for privileged modificationsCheck Group Policy Preferences that modify local users and groups: navigate to Computer Configuration > Preferences > Control Panel > Local Users and Groups in gpmc.msc. Also examine registry policies at HKLM\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Run and similar Run keys.Affected if Group Policy Preferences are configured to modify user accounts, groups, or run items at logon, creating potential escalation paths.
You are affected if your Windows build number is below the fixed versions listed AND your system is domain-joined with Group Policy settings configured for software installation, scripts, or preference items that can be modified by a local authenticated user.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data10.0.14393.933910.0.17763.902010.0.19044.7548
Apply Microsoft security updates for Windows when available, review Group Policy configurations for overly permissive settings, and follow least-privilege principles to limit the impact of compromised accounts.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-50391 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-50391 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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