High severity · published Feb 10, 2026
CVE-2026-21218
.NET Spoofing Vulnerability
7.5
CVSS
1%
EPSS
No
On KEV
Description
Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 63% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
N1
.NET 10.0 · Microsoft
10.0.0 before 10.0.3 · source: vendor
N8
.NET 8.0 · Microsoft
8.0.0 before 8.0.24 · source: vendor
N9
.NET 9.0 · Microsoft
9.0.0 before 9.0.13 · source: vendor
NE
.net · Microsoft
8.0.0 before 8.0.24; 9.0.0 before 9.0.13; 10.0.0 before 10.0.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21218
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21218
Vendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21218
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