CVE-2026-47300: 
Visual Studio 2022 vulnerability analysis and mitigation

CVE-2026-47300 is an Elevation of Privilege vulnerability caused by an incorrect implementation of an authentication algorithm in ASP.NET Core. It allows an authenticated attacker with low privileges to elevate their privileges over a network. Affected products include .NET 8.0 (before 8.0.29), .NET 9.0 (before 9.0.18), .NET 10.0 (before 10.0.6), Microsoft Visual Studio 2022 versions 17.12 (before 17.12.22) and 17.14 (before 17.14.36), and Microsoft Visual Studio 2026 version 18.7 (before 18.7.4). The vulnerability was disclosed and patched on July 14, 2026, as part of Microsoft's July 2026 Patch Tuesday. It carries a CVSS v3.1 base score of 8.8 (High) (Microsoft MSRC, BleepingComputer).

The root cause is classified as CWE-303 (Incorrect Implementation of Authentication Algorithm), which maps to CAPEC-90 (Reflection Attack in Authentication Protocol). The flaw exists within ASP.NET Core's authentication handling, where an incorrect algorithmic implementation can be abused by a low-privileged, authenticated attacker to bypass privilege boundaries over a network without requiring user interaction. The attack vector is network-based with low attack complexity, meaning exploitation does not require special conditions beyond having a valid low-privilege account. No public proof-of-concept or detailed technical write-up has been published as of the disclosure date (Microsoft MSRC, .NET Announcements).

Successful exploitation grants an attacker high-level access across confidentiality, integrity, and availability — all three impact dimensions are rated High. An attacker who starts with low-privileged network access could read sensitive application data, modify system configurations or application data, and potentially disrupt service availability. The scope is limited to the affected system, but privilege escalation within a .NET or ASP.NET Core application could enable further lateral movement within the environment depending on the application's role and data access (Microsoft MSRC).

Microsoft released patches on July 14, 2026, as part of the July 2026 Patch Tuesday update cycle. Organizations should update to the following fixed versions immediately: .NET 8.0.29, .NET 9.0.18, .NET 10.0.6, Visual Studio 2022 17.12.22, Visual Studio 2022 17.14.36, and Visual Studio 2026 18.7.4. No configuration-based workarounds have been published; upgrading to a patched version is the only recommended remediation. Additionally, monitoring for unexpected privilege escalations or authentication anomalies in ASP.NET Core applications is advised as a compensating control (Microsoft MSRC, .NET Dev Blog).

The vulnerability was covered as part of Microsoft's July 2026 Patch Tuesday, which was notably large, fixing a reported 570 flaws including three zero-days. Security outlets such as BleepingComputer and Rapid7 included CVE-2026-47300 in their Patch Tuesday roundups, highlighting it as a network-exploitable privilege escalation in widely deployed .NET and Visual Studio products. The SANS Internet Storm Center also noted the patch in their July 2026 diary entry. No significant independent researcher commentary or social media controversy has been observed specific to this CVE (BleepingComputer, Rapid7, SANS ISC).