Vulnerability in Microsoft .Net 10.0

CVE-2026-21218

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

EPSS: 0.000 (14.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: 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.

Affected products

Microsoft .Net 10.0 — versions 10.0.0
Microsoft .Net 8.0 — versions 8.0.0
Microsoft .Net 9.0 — versions 9.0.0

Weakness classification (CWE)

CWE-166

References

.NET Spoofing Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-21218?: CVE-2026-21218 is a high-severity vulnerability in Microsoft .Net 10.0, classified under CWE-166. CVSS score: 7.5/10. Published 2026-02-10.
How severe is CVE-2026-21218?: High severity. CVSS v3 base score is 7.5 out of 10.