CVE-2026-47303
High CVSS 8.8Published 2026-07-14 ยท last changed 2026-07-22
The fix
Microsoft fixes this in updatesKB5104032, KB5104033. The fixed build differs per Windows version, so the row that matters is the one matching the machine you are looking at.
| Windows version | Fixed in build | Update | Released |
|---|---|---|---|
| .NET 8.0 installed on Windows | 8.0.29 | KB5104032 | 2026-09-20 |
| .NET 9.0 installed on Windows | 9.0.18 | KB5104033 | 2026-09-20 |
Having the KB is not the same as knowing whether a machine has it. Windows updates supersede each other, so the update you installed often covers a fix that shipped in an earlier one. Paste your build into the patch checker and it walks that chain for you.
What it is
Authentication bypass by assumed-immutable data in ASP.NET Core allows an authorized attacker to elevate privileges over a network.
Sources
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H