CVE-2026-23666

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-23666
Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

7.5 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23666 Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-23666
https://bugzilla.redhat.com/show_bug.cgi?id=2458271
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23666.json
Configurations

Configuration 1 (hide)

AND
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*

Configuration 2 (hide)

AND
OR cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:*

Configuration 3 (hide)

AND
OR cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:*

Configuration 4 (hide)

AND
OR cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2025:-:*:*:*:*:*:x64:*

Configuration 5 (hide)

AND
OR cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*

Configuration 6 (hide)

AND
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
OR cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
History

30 Jun 2026, 03:17

Type Values Removed Values Added
CWE CWE-366
References
  • () https://access.redhat.com/security/cve/CVE-2026-23666 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2458271 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23666.json -

07 May 2026, 19:46

Type Values Removed Values Added
First Time Microsoft windows Server 2012
Microsoft windows Server 2025
Microsoft windows 10 21h2
Microsoft windows 11 22h2
Microsoft windows Server 2022 23h2
Microsoft windows Server 2022
Microsoft
Microsoft windows 11 26h1
Microsoft windows 11 23h2
Microsoft windows 10 1607
Microsoft .net Framework
Microsoft windows 10 1809
Microsoft windows 11 25h2
Microsoft windows 10 22h2
Microsoft windows 11 24h2
References () https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23666 - () https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23666 - Vendor Advisory
CPE cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:arm64:*
cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:-:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:*
cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*

15 Apr 2026, 22:16

Type Values Removed Values Added
Summary (en) Concurrent execution using shared resource with improper synchronization ('race condition') in .NET Framework allows an unauthorized attacker to deny service over a network. (en) Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

14 Apr 2026, 18:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-04-14 18:16

Updated : 2026-07-15 02:18

NVD link : CVE-2026-23666

Mitre link : CVE-2026-23666

CVE.ORG link : CVE-2026-23666

JSON object : View

Products Affected

microsoft

  • windows_11_25h2
  • windows_10_1607
  • windows_11_24h2
  • windows_10_1809
  • windows_11_22h2
  • windows_server_2012
  • windows_10_22h2
  • windows_11_23h2
  • windows_11_26h1
  • windows_server_2022_23h2
  • windows_10_21h2
  • windows_server_2022
  • .net_framework
  • windows_server_2025
CWE
CWE-755

Improper Handling of Exceptional Conditions

CWE-366

Race Condition within a Thread