Microsoft Patches .NET Framework CLR Escalation on Windows 11 23H2 with KB5082424
The April 2026 cumulative update for .NET Framework 3.5 and 4.8.1 on Windows 11 23H2 patches CLR privilege escalation and ASP.NET stability issues. Superseded by KB5087058 (May).
On this page
Key takeaways
- CVE-2026-0847: CLR GC privilege escalation affecting all .NET Framework apps.
- 23H2-specific companion to KB5082420 (24H2) and KB5082417 (25H2).
- Superseded by KB5087058 (May 2026). No known issues.
What to do now
High urgency- Install KB5087058 (supersedes KB5082424).
Microsoft released KB5082424 on April 14, 2026, a cumulative security update for .NET Framework 3.5 and 4.8.1 on Windows 11 23H2 patching CVE-2026-0847, a CLR privilege escalation via the garbage collector.
Same CVE as KB5082420 (24H2) and KB5082417 (25H2). All three target different Windows 11 versions with the same .NET Framework fix.
KB5082424 patches CVE-2026-0847 CLR escalation in .NET Framework on Windows 11 23H2.
.NET Framework 3.5/4.8.1 on Win 11 23H2: CVE-2026-0847 CLR GC EoP. Superseded by KB5087058.
Affected & context
April 2026 .NET Framework cumulative update for Windows 11 23H2.
CLR GC escalation affects every .NET Framework app.
Windows 11 23H2 with .NET Framework 3.5/4.8.1.
- Vendors
- Microsoft
- Products
- .NET Framework 3.5 (Windows 11 23H2).NET Framework 4.8.1 (Windows 11 23H2)
- CVEs
- CVE-2026-0847
KB5082424 Patches CLR Privilege Escalation on Windows 11 23H2
Microsoft released KB5082424 on April 14, 2026, a cumulative security update for .NET Framework 3.5 and 4.8.1 on Windows 11 Version 23H2. The update patches CVE-2026-0847 (CLR privilege escalation via garbage collector) and includes ASP.NET stability improvements. It is the 23H2-specific companion to KB5082420 (24H2) and KB5082417 (25H2), all released on the same Patch Tuesday.
This update is superseded by KB5087058 (May 2026). Organizations should install the latest available .NET Framework cumulative update.
CLR GC Escalation Affects All .NET Framework Apps
CVE-2026-0847 affects the CLR garbage collector used by every .NET Framework application. The 23H2 branch remains widely deployed, making this a routine but important Patch Tuesday update for .NET workloads.
Windows 11 23H2 with .NET Framework
Windows 11 23H2 (x64 and ARM64) with .NET Framework 3.5 and/or 4.8.1. Restart required. Superseded by KB5087058 (May). No known issues.
Timeline
KB5082424 released
Microsoft releases KB5082424 as April Patch Tuesday .NET Framework update for Windows 11 23H2.
Source: Microsoft Support
Confidence: High
Impact
CLR privilege escalation and ASP.NET stability fix for .NET Framework on Windows 11 23H2.
Business impact
CLR escalation affects every .NET Framework app on the system.
Security impact
CVE-2026-0847 enables privilege escalation through the CLR garbage collector.
Affected audience: Windows 11 23H2 users with .NET Framework
Action required.
Technical details
- CVEs
- CVE-2026-0847
Response
Response status: Patched
Patch available: Yes
Workaround available: No
FAQ
What does KB5082424 fix?
CVE-2026-0847 (CLR garbage collector privilege escalation) and ASP.NET stability improvements for Windows 11 23H2.
Which systems need this?
Windows 11 23H2 (x64 and ARM64) with .NET Framework 3.5 and/or 4.8.1.
Is this superseded?
Yes. KB5087058 (May 2026) supersedes it. Install the latest available update.
The bottom line
KB5082424 patches CVE-2026-0847 (CLR GC privilege escalation) in .NET Framework 3.5/4.8.1 on Windows 11 23H2. Superseded by KB5087058.
Standard Patch Tuesday .NET Framework update for 23H2. Install KB5087058 (May) which supersedes this.
What happens next
KB5087058 (May) supersedes this update.
What to do
Install KB5087058 or latest .NET Framework update for Windows 11 23H2.