.NET and Visual Studio Remote Code Execution Vulnerability

Assessment

Heap-based buffer overflow in Visual Studio allows an unauthorized attacker to execute code over a network.

Severity
Important
CVSS base score
8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact
Remote Code Execution
EPSS, next 30 days
0.9%Higher than 58.5% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
Exploitability
Exploitation Unlikely
Publicly disclosed
No
Customer action
Required: apply the update
Component
Visual Studio
Weakness
CWE-122: Heap-based Buffer Overflow
Issued by
Microsoft
Published
8 Sep 2026 · September 2026
Last revised
25 Sep 2026Security Updates table updated provide links to the KB articles and download center updates. Microsoft recommends installing the updates.

Updates that fix it

18 KBs
KBTypeRestartApplies toOther CVEs
KB5123099 Security Update — Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit Systems, Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based Systems, Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 All CVEs in KB5123099
KB5126043 Security Update — Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019, Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems, Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for ARM64-based Systems and 1 more All CVEs in KB5126043
KB5126044 Security Update — Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 All CVEs in KB5126044
KB5126045 Security Update — Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 All CVEs in KB5126045
KB5126046 Security Update — Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for 32-bit Systems, Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for ARM64-based Systems, Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for x64-based Systems and 3 more All CVEs in KB5126046
KB5126047 Security Update — Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit Systems, Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems, Microsoft .NET Framework 4.8 on Windows Server 2016 All CVEs in KB5126047
KB5126048 Security Update — Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 All CVEs in KB5126048
KB5126049 Security Update — Microsoft .NET Framework 4.8 on Windows Server 2012 All CVEs in KB5126049
KB5126050 Security Update — Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022 All CVEs in KB5126050
KB5126051 Security Update — Microsoft .NET Framework 4.8 on Windows Server 2012 R2 All CVEs in KB5126051
KB5126052 Security Update — Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for ARM64-based Systems, Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for x64-based Systems, Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for ARM64-based Systems and 2 more All CVEs in KB5126052
KB5126053 Security Update — Microsoft .NET Framework 4.8.1 on Windows 11 Version 26H1 for ARM64-based Systems, Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1 for x64-based Systems All CVEs in KB5126053
KB5126104 Security Update — .NET 8.0 installed on Windows All CVEs in KB5126104
KB5126105 Security Update — .NET 9.0 installed on Windows All CVEs in KB5126105
KB5126106 Security Update — .NET 10.0 installed on Windows All CVEs in KB5126106
KB5126421 Security Update — Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for 32-bit Systems, Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for ARM64-based Systems, Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for x64-based Systems and 6 more All CVEs in KB5126421
KB5126422 Security Update — Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022 All CVEs in KB5126422
KB5126424 Security Update — Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for ARM64-based Systems, Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for x64-based Systems All CVEs in KB5126424

Affected products

Developer Tools
47 affected products
  • .NET 10.0 installed on Windows
  • .NET 11.0 installed on Windows
  • .NET 8.0 installed on Windows
  • .NET 9.0 installed on Windows
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019
  • Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 21H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 22H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019
  • Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2022
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 21H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for 32-bit Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 10 Version 22H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 23H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 24H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for ARM64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for x64-based Systems
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2022
  • Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025
  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012
  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2
  • Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit Systems
  • Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems
  • Microsoft .NET Framework 4.8 on Windows Server 2012
  • Microsoft .NET Framework 4.8 on Windows Server 2012 R2
  • Microsoft .NET Framework 4.8 on Windows Server 2016
  • Microsoft .NET Framework 4.8.1 on Windows 11 Version 26H1 for ARM64-based Systems
  • Microsoft .NET Framework 4.8.1 on Windows 11 version 26H1 for x64-based Systems
  • Microsoft Visual Studio 2022 version 17.14
  • Microsoft Visual Studio 2026 version 18.9
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