What’s Vulnerable › Vulnerabilities
CVE-2026-21218: .NET Spoofing Vulnerability
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.0% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-02-10 · updated 2026-08-19
- Weakness: CWE-166
Description
Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.
Affected products
- Microsoft .NET: from 8.0.0 before 8.0.24; from 9.0.0 before 9.0.13; from 10.0.0 before 10.0.3 — fixed in 10.0.3, 8.0.24, 9.0.13
- Microsoft .NET: from 10.0.0 before 10.0.3 — fixed in 10.0.3
- Microsoft .NET 8.0: from 8.0.0 before 8.0.24 — fixed in 8.0.24
- Microsoft .NET 9.0: from 9.0.0 before 9.0.13 — fixed in 9.0.13
How to fix
Upgrade to a fixed version: Microsoft .NET 10.0.3, 8.0.24, 9.0.13; Microsoft .NET 10.0.3; Microsoft .NET 8.0 8.0.24; Microsoft .NET 9.0 9.0.13. Check the vendor advisory for mitigations.
References
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