CVE-2026-21218 Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network

Description

Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.

Affected products and versions

Product	Affected versions	Fixed in
.NET 10.0 10.0	10.0.0 → < 10.0.3	10.0.3
.NET 8.0 8.0	8.0.0 → < 8.0.24	8.0.24
.NET 9.0 9.0	9.0.0 → < 9.0.13	9.0.13

Other CVEs of .NET 10.0

The 70 CVEs of .NET 10.0 →

CVE-2026-105016 Heap-based buffer overflow in Microsoft QUIC allows an unauthorized attacker to execute code over a network 9.8 Critical CVE-2026-58280 Uncontrolled recursion in .NET allows an unauthorized attacker to deny service over a network 7.5 High CVE-2026-96957 Improper verification of cryptographic signature in .NET allows an unauthorized attacker to bypass a security feature… 8.8 High CVE-2026-96235 Out-of-bounds write in .NET allows an unauthorized attacker to execute code over a network 8.8 High