CVE-2026-62909
High CVSS 7.8Published 2026-08-11 ยท last changed 2026-08-14
The fix
Microsoft fixes this in updatesKB5122106, KB5122104, KB5122105. 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 10.0 installed on Windows | 10.0.11 | KB5122106 | 2026-09-20 |
| .NET 8.0 installed on Windows | 8.0.30 | KB5122104 | 2026-09-20 |
| .NET 9.0 installed on Windows | 9.0.19 | KB5122105 | 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
Uncaught exception in .NET allows an authorized attacker to elevate privileges locally.
Sources
CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H