.NET Framework Denial of Service Vulnerability
Priority MEDIUM 42CWE-755Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.
Summary
Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0133 71st percentileScored 2026-11-07
Fix Fixed Microsoft: 18 updates
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Microsoft .NET Framework 3.5 | 3.5.0 to before 2.0.50727.8982 & 3.0.30729.8976 | 2.0.50727.8982 & 3.0.30729.8976 | Patch available | CNA |
| Microsoft | Microsoft .NET Framework 3.5 AND 4.7.2 | 4.7.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0 | 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0 | Patch available | CNA |
| Microsoft | Microsoft .NET Framework 3.5 AND 4.8 | 4.8.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0 | 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0 | Patch available | CNA |
| Microsoft | Microsoft .NET Framework 3.5 AND 4.8.1 | 4.8.1 to before 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0 | 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0 | Patch available | CNA |
| Microsoft | Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 | 4.7.0 to before 4.8.4801.0 | 4.8.4801.0 | Patch available | CNA |
| Microsoft | Microsoft .NET Framework 4.8 | 4.8.0 to before 4.8.4801.0 | 4.8.4801.0 | Patch available | CNA |
- Microsoft .NET Framework 3.5 VendorMicrosoft Affected 3.5.0 to before 2.0.50727.8982 & 3.0.30729.8976 Fixed in 2.0.50727.8982 & 3.0.30729.8976 Patch available CNA
- Microsoft .NET Framework 3.5 AND 4.7.2 VendorMicrosoft Affected 4.7.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0 Fixed in 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0 Patch available CNA
- Microsoft .NET Framework 3.5 AND 4.8 VendorMicrosoft Affected 4.8.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0 Fixed in 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0 Patch available CNA
- Microsoft .NET Framework 3.5 AND 4.8.1 VendorMicrosoft Affected 4.8.1 to before 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0 Fixed in 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0 Patch available CNA
- Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 VendorMicrosoft Affected 4.7.0 to before 4.8.4801.0 Fixed in 4.8.4801.0 Patch available CNA
- Microsoft .NET Framework 4.8 VendorMicrosoft Affected 4.8.0 to before 4.8.4801.0 Fixed in 4.8.4801.0 Patch available CNA
CPE configurations NVD · 33
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:* | 3.5 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* | r2 | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:* | 4.7.2 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:* | 4.8 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
- cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:* Versions 3.5 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* Versions r2 Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:* Versions 4.7.2 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:* Versions 4.8 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
Show 23 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:* | 4.8.1 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:arm64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022_23h2:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2025:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:* | 4.6.2 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:* | 4.7 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:* | 4.7.1 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x64:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x86:* | not specified by NVD | Running on | Microsoft |
- cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:* Versions 4.8.1 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_23h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_24h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:arm64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_11_26h1:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022_23h2:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2025:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:* Versions 4.6.2 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:* Versions 4.7 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:* Versions 4.7.1 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x64:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x86:* Versions not specified by NVD Running on ·Microsoft
Remediation
Microsoft 18 updates
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9181 & 3.0.30729.9165 & 4.8.4801.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9181 & 3.0.30729.9165 & 4.8.4801.0
- Microsoft .NET Framework 4.8 2.0.50727.9181 & 3.0.30729.9165 & 4.8.4801.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Microsoft .NET Framework 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
Show 15 more Microsoft updates
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Microsoft .NET Framework 4.8 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0
- Security Update
- Microsoft .NET Framework 3.5 AND 4.7.2 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0
- Microsoft .NET Framework 4.7.2 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0
- Security Update
- Microsoft .NET Framework 4.8 4.8.4801.0
- Security Update
- Microsoft .NET Framework 3.5 2.0.50727.8982 & 3.0.30729.8976
- Security Update
- Microsoft .NET Framework 4.8 4.8.4801.0
- Security Update
- Microsoft .NET Framework 4.8 4.8.4801.0
- Security Update
- Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 4.7.4141.0
- Security Update
- Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 4.8.4801.0
- Security Update
- Microsoft .NET Framework 3.5 2.0.50727.8982 & 3.0.30729.8976
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
Not affected: 4 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images
Microsoft
Microsoft's page for this CVE →
- Impact
- Denial of Service
- Exploited
- No
- Publicly disclosed
- No
- Exploitability
- Exploitation Less Likely
Timeline
- 2026-10-02 Threatist record created from CVE-2026-23666
- 2026-10-03 Alias added: GHSA-fvc9-q887-5p2h
References
More Microsoft .net Framework vulnerabilities
- TI-2020-00622 XML injection in Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01112 A remote code execution vulnerability exists in .NET Framework, Microsoft SharePoint, and… KEVCVSS 3.1HIGH 7.8
- TI-2017-06273 Code injection in Microsoft .NET Framework KEVCVSS 3.1HIGH 7.8
- TI-2015-01495 The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0 SP2, 3.5, 3.5.1… KEVCVSS 3.1HIGH 7.8
- TI-2024-19239 .NET Framework Information Disclosure Vulnerability KEVCVSS 3.1HIGH 7.5
- TI-2023-18684 ASP.NET Elevation of Privilege Vulnerability CVSS 3.1HIGH 8.8
Sources
- CVE-2026-23666 · CVE Program
- CVE-2026-23666 · NVD
- FIRST EPSS
- GHSA-fvc9-q887-5p2h · GitHub Advisory Database · CC BY 4.0
- CVE-2026-23666 · Microsoft Security Update Guide
- CVE-2026-23666 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences