Heap-based buffer overflow in Microsoft products - CVE-2025-21171

Vulnerability identifier: #VU102801

CSH Severity: Medium

CVSS v4: 7.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2025-21171

CWE-ID: CWE-122

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in .NET. A remote attacker can pass specially crafted data to the application, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

.NET for macOS
.NET for Linux
Visual Studio
PowerShell for Linux
PowerShell for macOS
.NET
PowerShell
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for IBM z Systems
Ubuntu
Fedora
dotnet-runtime-8.0 (Ubuntu package)
aspnetcore-runtime-8.0 (Ubuntu package)
dotnet-hostfxr-8.0 (Ubuntu package)
dotnet-host-8.0 (Ubuntu package)
dotnet-sdk-8.0 (Ubuntu package)
dotnet8 (Ubuntu package)
aspnetcore-runtime-9.0 (Ubuntu package)
dotnet-runtime-9.0 (Ubuntu package)
dotnet-host-9.0 (Ubuntu package)
dotnet-hostfxr-9.0 (Ubuntu package)
dotnet-sdk-9.0 (Ubuntu package)
dotnet9.0 (Red Hat package)
dotnet9.0
dotnet9 (Ubuntu package)

Install updates from vendor's website.

.NET for macOS - update to 9.0.1 9.0.1
.NET - update to 9.0.1
.NET for Linux - update to 9.0.1 9.0.1
Visual Studio - addressed in versions 17.6.22 17.6.35707.66, 17.8.17 17.8.35707.121, 17.10.10 17.10.35707.196, 17.12.4 17.12.35707.178
PowerShell - update to 7.5.0
PowerShell for Linux - update to 7.5.0 7.5.0
PowerShell for macOS - update to 7.5.0 7.5.0
dotnet-runtime-8.0 (Ubuntu package) - addressed in versions 8.0.12-0ubuntu1~22.04.1, 8.0.12-0ubuntu1~24.04.1, 8.0.12-0ubuntu1~24.10.1
aspnetcore-runtime-8.0 (Ubuntu package) - addressed in versions 8.0.12-0ubuntu1~22.04.1, 8.0.12-0ubuntu1~24.04.1, 8.0.12-0ubuntu1~24.10.1
dotnet-hostfxr-8.0 (Ubuntu package) - addressed in versions 8.0.12-0ubuntu1~22.04.1, 8.0.12-0ubuntu1~24.04.1, 8.0.12-0ubuntu1~24.10.1
dotnet-host-8.0 (Ubuntu package) - addressed in versions 8.0.12-0ubuntu1~22.04.1, 8.0.12-0ubuntu1~24.04.1, 8.0.12-0ubuntu1~24.10.1
dotnet-sdk-8.0 (Ubuntu package) - addressed in versions 8.0.112-0ubuntu1~22.04.1, 8.0.112-0ubuntu1~24.04.1, 8.0.112-0ubuntu1~24.10.1
dotnet8 (Ubuntu package) - addressed in versions 8.0.112-8.0.12-0ubuntu1~22.04.1, 8.0.112-8.0.12-0ubuntu1~24.04.1, 8.0.112-8.0.12-0ubuntu1~24.10.1
aspnetcore-runtime-9.0 (Ubuntu package) - update to 9.0.1-0ubuntu1~24.10.1
dotnet-runtime-9.0 (Ubuntu package) - update to 9.0.1-0ubuntu1~24.10.1
dotnet-host-9.0 (Ubuntu package) - update to 9.0.1-0ubuntu1~24.10.1
dotnet-hostfxr-9.0 (Ubuntu package) - update to 9.0.1-0ubuntu1~24.10.1
dotnet-sdk-9.0 (Ubuntu package) - update to 9.0.102-0ubuntu1~24.10.1
dotnet9.0 (Red Hat package) - update to 9.0.102-1.el8_10
dotnet9.0 - addressed in versions 9.0.102-1.fc40, 9.0.102-1.fc41
dotnet9 (Ubuntu package) - update to 9.0.102-9.0.1-0ubuntu1~24.10.1

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21171

• Multiple vulnerabilities in Microsoft .NET
• Ubuntu update for dotnet8
• Red Hat Enterprise Linux 8 update for .NET 9.0
• Fedora 41 update for dotnet9.0
• Fedora 40 update for dotnet9.0