Security Update for Microsoft .NET Core (May 2026)

high Nessus Plugin ID 314679

Synopsis

The remote Windows host is affected by a .NET Core vulnerability

Description

The version of tested product installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the vendor advisory.

- A tampering vulnerability exists when .NET Core improperly handles specially crafted files. An attacker who successfully exploited this vulnerability could write arbitrary files and directories to certain locations on a vulnerable system. However, an attacker would have limited control over the destination of the files and directories. To exploit the vulnerability, an attacker must send a specially crafted file to a vulnerable system. The security update fixes the vulnerability by ensuring .NET Core properly handles files. (CVE-2026-32175)

- Heap-based buffer overflow in .NET allows an unauthorized attacker to elevate privileges locally.
(CVE-2026-32177)

- Improper input validation in .NET allows an unauthorized attacker to elevate privileges locally.
(CVE-2026-35433)

- Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny service over a network. (CVE-2026-42899)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update .NET Core, remove vulnerable packages and refer to vendor advisory.

Plugin Details

Severity: High

ID: 314679

File Name: smb_nt_ms26_may_dotnet_core.nasl

Version: 1.1

Type: Local

Agent: windows

Family: Windows

Published: 5/14/2026

Updated: 5/14/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.3

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2026-32175

CVSS v3

Risk Factor: High

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Vulnerability Information

CPE: cpe:/a:microsoft:.net_core

Required KB Items: installed_sw/.NET Core Windows

Patch Publication Date: 5/12/2026

Vulnerability Publication Date: 5/12/2026

Reference Information

CVE: CVE-2026-32175, CVE-2026-32177, CVE-2026-35433, CVE-2026-42899

MSFT: MS26-5093446, MS26-5093447, MS26-5093448

MSKB: 5093446, 5093447, 5093448

Detections

Analytics