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01 Record

CVE-2026-23666

.NET Framework Denial of Service Vulnerability

HighPUBLISHEDCNA: microsoft
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
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02 Description

.NET Framework Denial of Service Vulnerability

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
1.33% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 70.6% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-10-26.
Red Hat severity
Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-04-14 16:57Z6 MO AGO
Last updated
2026-10-15 15:53Z14 DAYS AGO
Reserved
2026-01-14
Assigning CNA
microsoft
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
Weaknesses
  • CWE-755Improper Handling of Exceptional ConditionsClass
  • CWE-366Race Condition within a ThreadBase
Data version
5.2
Document digest
eae76aaae30b069e0615649d8822d2f42500b431359e9e5106d117f83fea2870

05 Affected products

VendorProductVersionsPlatforms
MicrosoftMicrosoft .NET Framework 3.53.5.0 to < 2.0.50727.8982 & 3.0.30729.8976Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)
MicrosoftMicrosoft .NET Framework 3.5 AND 4.7.24.7.0 to < 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for ARM64-based Systems, Windows 10 Version 1809 for x64-based Systems
MicrosoftMicrosoft .NET Framework 3.5 AND 4.84.8.0 to < 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for ARM64-based Systems, Windows 10 Version 1809 for x64-based Systems, Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 22H2 for x64-based Systems, Windows Server 2022, Windows Server 2022 (Server Core installation)
MicrosoftMicrosoft .NET Framework 3.5 AND 4.8.14.8.1 to < 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 22H2 for x64-based Systems, Windows 11 Version 22H2 for ARM64-based Systems, Windows 11 Version 22H2 for x64-based Systems, Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems, Windows Server 2022, Windows Server 2022 (Server Core installation), Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025, Windows Server 2025 (Server Core installation)
MicrosoftMicrosoft .NET Framework 4.6.2/4.7/4.7.1/4.7.24.7.0 to < 4.8.4801.0Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)
MicrosoftMicrosoft .NET Framework 4.84.8.0 to < 4.8.4801.0Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems, Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)

06 References