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HIGH · 7.5

CVE-2026-23666

Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

Vulnerability Description

Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
Microsoft.Net Framework3.5
MicrosoftWindows Server 2012-
MicrosoftWindows 10 1809-
MicrosoftWindows 10 21H2-
MicrosoftWindows 10 22H2-
MicrosoftWindows Server 2022-
MicrosoftWindows 11 22H2-
MicrosoftWindows 11 23H2-
MicrosoftWindows 11 24H2-
MicrosoftWindows 11 25H2-
MicrosoftWindows 11 26H1-
MicrosoftWindows Server 2022 23H2-
MicrosoftWindows Server 2025-
MicrosoftWindows 10 1607-

Related Weaknesses (CWE)

CWE-755

References

FAQ

What is CVE-2026-23666?

CVE-2026-23666 is a vulnerability with a CVSS score of 7.5 (HIGH). Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

How severe is CVE-2026-23666?

CVE-2026-23666 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-23666?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft .Net Framework, Microsoft Windows Server 2012, Microsoft Windows 10 1809, Microsoft Windows 10 21H2, Microsoft Windows 10 22H2.