Executive brief
A security vulnerability exists in Microsoft .NET and .NET Framework, which are widely used platforms for building and running applications on Windows. An attacker who successfully exploits this flaw could gain higher-level system permissions than they should normally have. This could allow an unauthorized user to take control of an affected system, potentially leading to data theft or further malicious activity.
Technical details
A heap-based buffer overflow (CWE-122) exists in Microsoft .NET and .NET Framework due to improper input validation (CWE-20). The vulnerability is triggered when the software handles specially crafted input, leading to an out-of-bounds write (CWE-787). An attacker with local access can exploit this by convincing a user to interact with a malicious application or file (UI:R). Successful exploitation allows the attacker to elevate their privileges to a higher level, potentially gaining full control over the host environment. Microsoft has released security updates to address this issue across affected versions of .NET, .NET Framework, and Visual Studio.
Affected products
- Microsoft .NET 8.0.0 to 8.0.26, 9.0.0 to 9.0.15, 10.0.0 to 10.0.7
- Microsoft .NET Framework 3.5, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
- Microsoft Visual Studio 2022 17.12.0 to 17.12.19, 17.14.0 to 17.14.31
- Microsoft Visual Studio 2026 18.5.0 to 18.5.2
Timeline
- 2026-05-12: disclosed
- 2026-05-12: advisory