SB2025011545 - Multiple vulnerabilities in Microsoft .NET

Description

This security bulletin contains information about 2 vulnerabilities.

1) Creation of temporary file in directory with insecure permissions (CVE-ID: CVE-2025-21173)

CWE-ID: CWE-379 - Creation of Temporary File in Directory with Insecure Permissions

CVSSv4: 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/E:U/U:Clear

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.

2) Heap-based buffer overflow (CVE-ID: CVE-2025-21171)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 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/E:U/U:Green

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.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21173
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21171