# CVE-2026-21218

## Summary

- **CVE ID:** CVE-2026-21218
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C)
- **CWE:** CWE-166
- **Published:** Feb 10, 2026
- **Last Modified:** Aug 19, 2026

## Description

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

## Affected Products

- Microsoft — .NET 10.0 (10.0.0)
- Microsoft — .NET 8.0 (8.0.0)
- Microsoft — .NET 9.0 (9.0.0)

## References

- [CNA](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21218)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 1.03%
- **EPSS Percentile:** 61.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._