CVE-2026-109475: .NET Denial of Service Vulnerability
CVE-2026-109475 is a denial of service vulnerability in .NET, rated Important by Microsoft, with a CVSS 3.1 base score of 7.5 (High). An attacker can exploit it remotely over the network, without any privileges and without user interaction. Microsoft has not reported exploitation in the wild and rates exploitation as less likely. Microsoft released the fix on 10 November 2026 in the November 2026 Patch Tuesday, delivered through 3 security updates (KB5135241, KB5135243, KB5135242). It affects 8 products in 1 product family (Developer Tools).
Key facts
- CVE ID
- CVE-2026-109475
- Severity
- High CVSS 7.5
- Microsoft severity
- Important
- Impact
- Denial of Service
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- Weakness
- CWE-121
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- November 2026 Patch Tuesday
- Product families
- Developer Tools
CVSS score and vector
Microsoft scores CVE-2026-109475 at 7.5 (temporal 6.5) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | None |
| Integrity impact | None |
| Availability impact | High |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Stack-based buffer overflow in .NET allows an unauthorized attacker to deny service over a network.
Affected products (8)
Developer Tools
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| .NET 10.0 installed on Mac OS | KB5135241 | Security Update | 10.0.15 | |
| .NET 11.0 installed on Mac OS | Release Notes | Security Update | 11.0.0 | |
| .NET 8.0 installed on Mac OS | KB5135243 | Security Update | 8.0.34 | |
| .NET 9.0 installed on Mac OS | KB5135242 | Security Update | 9.0.23 | |
| .NET 8.0 installed on Linux | KB5135243 | Security Update | 8.0.34 | |
| .NET 9.0 installed on Linux | KB5135242 | Security Update | 9.0.23 | |
| .NET 10.0 installed on Linux | KB5135241 | Security Update | 10.0.15 | |
| .NET 11.0 installed on Linux | Release Notes | Security Update | 11.0.0 |
Security updates (3)
NIST NVD data
- NVD status
- Awaiting Analysis
- NVD CVSS
- 7.5 (HIGH)
- NVD weakness
- CWE-121
- Published to NVD
- NVD last modified
References
Acknowledgments
- Anonymous
- DEVENDRA KUMAR SINHA
- Kevin Schmidt
- Leandro Batista
- Rinku Das with Cyberwarefare
- Rolf Zengaffinen
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 2.0 | Changes made to the security updates links and information. This is an informational change only. |