CVE-2026-25667: Microsoft .net

High severity, CVSS 7.5. EPSS: 4.2% chance of exploitation in the next 30 days.

ASP.NET Core Kestrel in Microsoft .NET 8.0 before 8.0.22 and .NET 9.0 before 9.0.11 allows a remote attacker to cause excessive CPU consumption by sending a crafted QUIC packet, because of an incorrect exit condition for HTTP/3 Encoder/Decoder stream processing.

Affected products

• Microsoft .net: from 8.0.0, before 8.0.22 (fixed in 8.0.22); from 9.0.0, before 9.0.11 (fixed in 9.0.11)

Published 2026-03-19. Last modified 2026-06-17.