CVE-2026-21218
High
Description
Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Microsoft .net
PublishedFeb 10, 2026
First seenFeb 10, 2026
Weakness typeCWE-166CWE-166
How to fix
Update
- microsoft .net8.0.24, 9.0.13, 10.0.3 or later
- System.Security.Cryptography.Cose8.0.2, 9.0.13, 10.0.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| microsoft .net | 8.0.0 ≤ v < 8.0.24, 9.0.0 ≤ v < 9.0.13, 10.0.0 ≤ v < 10.0.3 | 8.0.24, 9.0.13, 10.0.3 |
| System.Security.Cryptography.CoseNuGet | 8.0.0 ≤ v < 8.0.2, 9.0.0 ≤ v < 9.0.13, 10.0.0 ≤ v < 10.0.3 | 8.0.2, 9.0.13, 10.0.3 |
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