Creation of temporary file in directory with insecure permissions in Microsoft products - CVE-2025-21173

Vulnerability identifier: #VU102800

CSH Severity: Low

CVSS v4: 7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2025-21173

CWE-ID: CWE-379

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privilege on the target system.

The vulnerability exists due to creation of temporary file in directory with insecure permissions in .NET. A local user can overwrite arbitrary file content and gain elevated privileges on the system.

.NET
.NET for Linux
Visual Studio
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat CodeReady Linux Builder for IBM z Systems
Ubuntu
Fedora
aspnetcore-runtime-8.0 (Ubuntu package)
dotnet-runtime-8.0 (Ubuntu package)
dotnet-host-8.0 (Ubuntu package)
dotnet-hostfxr-8.0 (Ubuntu package)
dotnet-sdk-8.0 (Ubuntu package)
dotnet8.0 (Red Hat package)
dotnet8.0
dotnet8 (Ubuntu package)
dotnet-runtime-9.0 (Ubuntu package)
dotnet-hostfxr-9.0 (Ubuntu package)
dotnet-host-9.0 (Ubuntu package)
aspnetcore-runtime-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 Linux - addressed in versions 8.0.12 8.0.12, 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
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-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-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-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-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
dotnet8.0 (Red Hat package) - addressed in versions 8.0.112-1.el8_10, 8.0.112-1.el9_4
dotnet8.0 - addressed in versions 8.0.112-1.fc40, 8.0.112-1.fc41
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
dotnet-runtime-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-host-9.0 (Ubuntu package) - update to 9.0.1-0ubuntu1~24.10.1
aspnetcore-runtime-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-2025-21173

• Multiple vulnerabilities in Microsoft .NET
• Ubuntu update for dotnet8
• Red Hat Enterprise Linux 8 update for .NET 8.0
• Red Hat Enterprise Linux 8 update for .NET 9.0
• Fedora 41 update for dotnet8.0
• Fedora 40 update for dotnet8.0
• Fedora 41 update for dotnet9.0
• Fedora 40 update for dotnet9.0
• Red Hat Enterprise Linux 9 update for .NET 8.0