CVE-2026-21218

Name: CVE-2026-21218
Creator: NVD / NIST
Published: 2026-02-10T18:16:22.967+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.01%

Last modified Jun 17, 2026

CVE-2026-21218 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.. EPSS estimates a 1.01% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

1.01%

58.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-166

Affected Software

Vendor	Product	Versions
Microsoft	.Net	>= 8.0.0, < 8.0.24
Microsoft	.Net	>= 9.0.0, < 9.0.13
Microsoft	.Net	>= 10.0.0, < 10.0.3

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21218Vendor Advisory

Timeline

Published: Feb 10, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-21218?

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

How severe is CVE-2026-21218?

CVE-2026-21218 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.01% probability of exploitation in the next 30 days.

How do I fix CVE-2026-21218?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21218?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST