CVE-2026-47300Important

ASP.NET Core Elevation of Privilege Vulnerability

Assessment

Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

Severity: Important
CVSS base score: 8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact: Elevation of Privilege
EPSS, next 30 days: 0.8%Higher than 54.1% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
Exploitability: Exploitation Less Likely
Publicly disclosed: No
Customer action: Required: apply the update
Component: ASP.NET Core
Weakness: CWE-303: Incorrect Implementation of Authentication Algorithm
Issued by: Microsoft
Published: 14 Jul 2026 · July 2026
Last revised: 14 Jul 2026

3 KBs

KB	Type	Restart	Applies to	Other CVEs
KB5104032	Security Update	—	.NET 8.0 installed on Linux, .NET 8.0 installed on Mac OS, .NET 8.0 installed on Windows	All CVEs in KB5104032
KB5104033	Security Update	—	.NET 9.0 installed on Linux, .NET 9.0 installed on Mac OS, .NET 9.0 installed on Windows	All CVEs in KB5104033
KB5104034	Security Update	—	.NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS	All CVEs in KB5104034

Developer Tools

11 affected products