Microsoft Ships KB5082142 April 2026 Security Update for Windows Server 2022
The cumulative security update addresses multiple high-severity flaws across core system components, network protocols, and authentication subsystems on Windows Server 2022.
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Key takeaways
- KB5082142 was released on April 14, 2026 for Windows Server 2022.
- It raises the OS build to 20348.5020 and requires a restart.
- The update patches RCE, privilege escalation, information disclosure, and DoS vulnerabilities.
- It applies to Standard, Datacenter, Essentials, and Server Core (x64).
- Some systems may hit install error 0x80070643 without at least 2 GB of free disk space.
What to do now
High urgency- Prioritize deployment on internet-facing and high-security servers.
- Validate compatibility in a test environment before broad rollout.
- Ensure at least 2 GB free disk space to avoid install error 0x80070643.
- Schedule a maintenance window for the required restart.
Microsoft released KB5082142, a critical cumulative security update for Windows Server 2022, on April 14, 2026. According to the update documentation, the patch resolves multiple high-severity vulnerabilities spanning remote code execution, privilege escalation, information disclosure, and denial-of-service conditions, and raises the operating system to build 20348.5020.
Because several of the addressed flaws are described as unauthenticated remote code execution issues in network-facing services, administrators are advised to prioritize deployment on internet-facing and high-security servers.
Microsoft's KB5082142 is a critical April 2026 security update patching multiple Windows Server 2022 vulnerabilities and updating the build to 20348.5020.
Install KB5082142 to patch critical Windows Server 2022 vulnerabilities; the update reaches build 20348.5020 and requires a restart. Free up disk space to avoid install failures.
Affected & context
Microsoft released KB5082142, a critical cumulative security update for Windows Server 2022, on April 14, 2026, raising the OS build to 20348.5020.
The update addresses remote code execution and privilege escalation flaws that could enable full server compromise if left unpatched, particularly on internet-facing systems.
Organizations running Windows Server 2022 Standard, Datacenter, Essentials, and Server Core on x64.
- Vendors
- Microsoft
- Products
- Windows Server 2022 StandardWindows Server 2022 DatacenterWindows Server 2022 EssentialsWindows Server 2022 Server Core
- Geography
- Global
What the update does
KB5082142 is a cumulative security update released on April 14, 2026 for Windows Server 2022. Per the update documentation, it resolves multiple vulnerabilities across core system services, network protocol implementations, and authentication mechanisms, and brings supported systems to build 20348.5020.
The documented vulnerability categories include remote code execution in network-facing components, privilege escalation that could yield SYSTEM-level access, information disclosure exposing sensitive system data, denial-of-service conditions causing instability, and security-bypass issues in authentication and authorization.
- Updates Windows Server 2022 to build 20348.5020
- Released April 14, 2026
Affected systems
According to the documentation, the update applies to the following Windows Server 2022 configurations on x64:
- Windows Server 2022 Standard (x64)
- Windows Server 2022 Datacenter (x64)
- Windows Server 2022 Essentials (x64)
- Windows Server 2022 Server Core (x64)
What was fixed
The update documentation attributes the vulnerabilities to improper input validation, memory management issues, and insufficient access controls in various components. The described fixes include:
- Improved input validation and bounds checking in network services to address memory-corruption RCE flaws.
- Enhanced token validation and stricter access-control enforcement to prevent privilege escalation.
- Improved memory clearing and access controls to mitigate information disclosure.
- Hardened error handling and resource management in network protocols to prevent denial-of-service conditions.
- Strengthened authentication and session management for server management interfaces.
No CVEs cited in source material
The provided material does not list specific CVE identifiers, CVSS scores, or exploitation status. Confirm exact CVEs against Microsoft's official Security Update Guide before publishing.
Deployment and verification
The update is delivered through Windows Update, the Microsoft Update Catalog, WSUS (Security Updates classification), and SCCM software update workflows. The standalone package supports both GUI and Server Core installations. The documentation lists an approximate 890 MB package size, a required restart, and a typical 15–30 minute install time.
After installation, administrators can confirm the build and patch state with PowerShell:
Get-ComputerInfo | Select-Object WindowsVersion, WindowsBuildLabEx
Get-HotFix -Id KB5082142A successful install should report build 20348.5020 and show KB5082142 in update history.
Known issues
- Installation may fail with error 0x80070643 if the system partition lacks free space; ensure at least 2 GB is available.
- A small number of systems may see brief network connectivity issues immediately after restart, typically clearing within 5–10 minutes.
- Some workloads may show temporary performance impact in the first 24 hours as components optimize.
Before you deploy
Test in a non-production environment first, schedule a maintenance window for the required restart, and confirm backups are in place.
Timeline
KB5082142 released
Microsoft releases the KB5082142 cumulative security update for Windows Server 2022, updating the build to 20348.5020.
Source: KB5082142 update documentation
Confidence: Medium
Impact
Unpatched Windows Server 2022 systems remain exposed to remote code execution, privilege escalation, information disclosure, and denial-of-service attacks until KB5082142 is applied.
Business impact
Delayed patching increases the risk of server compromise, service disruption, and data exposure in enterprise environments.
Technical impact
Applies cumulative fixes to kernel components, network protocol stack, authentication subsystems, and management interfaces; requires a restart.
Security impact
Addresses unauthenticated RCE and privilege escalation flaws that, if chained, could enable full system compromise.
Privacy impact
Information disclosure flaws could expose sensitive system memory or configuration data if left unpatched.
Affected audience: System administrators, MSPs, IT security teams
Action required.
Technical details
- Attack vector
- Network and local, per documented vulnerability categories
- Affected versions
- Windows Server 2022 (pre-20348.5020)
- Patched versions
- 20348.5020
Detection methods
- Verify build number via Get-ComputerInfo
- Confirm patch install via Get-HotFix -Id KB5082142
- Check System event log for installation events
Mitigations
- Install KB5082142 through Windows Update, Microsoft Update Catalog, WSUS, or SCCM
Workarounds
- For install failures, free disk space and retry
- For post-restart network issues, wait ~10 minutes before troubleshooting
Response
Customer guidance
Microsoft's update documentation advises prioritizing deployment on internet-facing and high-security servers, testing in non-production first, and planning for a required restart.
Response status: Patched
Patch available: Yes
Workaround available: Yes
FAQ
What does KB5082142 resolve?
It resolves multiple critical vulnerabilities in Windows Server 2022, including remote code execution, privilege escalation, information disclosure, and denial-of-service conditions across core system components, network protocols, and authentication mechanisms.
Which systems require KB5082142?
It applies to Windows Server 2022 Standard, Datacenter, Essentials, and Server Core editions on x64.
What build number does KB5082142 install?
It updates Windows Server 2022 to build 20348.5020.
How do I verify KB5082142 is installed?
Run Get-HotFix -Id KB5082142 to confirm the patch, and Get-ComputerInfo to confirm the system reports build 20348.5020.
Why might installation fail with error 0x80070643?
This error can occur when the system partition lacks sufficient free space. Ensure at least 2 GB of free disk space and retry the installation.
The bottom line
KB5082142 is a critical April 14, 2026 security update for Windows Server 2022 that patches RCE, privilege escalation, information disclosure, and DoS flaws and raises the build to 20348.5020.
Treat KB5082142 as a high-priority patch, especially for internet-facing Windows Server 2022 hosts.
What happens next
Administrators should validate and roll out the update, starting with the most exposed systems, and confirm the resulting build.
What to do
Deploy KB5082142 and verify build 20348.5020 after restart.
Sources
Microsoft · Apr 14, 2026 · Primary source
Claims supported
- KB5082142 released April 14, 2026 and updates the build to 20348.5020
- Update addresses RCE, privilege escalation, information disclosure, and DoS vulnerabilities
- Applies to Windows Server 2022 Standard, Datacenter, Essentials, and Server Core (x64)
- Known issues include install error 0x80070643 and post-restart network delays