CVE-2026-118746: .NET Security Feature Bypass Vulnerability
CVE-2026-118746 is a security feature bypass vulnerability in .NET, rated Important by Microsoft, with a CVSS 3.1 base score of 6.8 (Medium). An attacker can exploit it remotely over the network, without any privileges and only if a user takes an action. 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. It affects 2 products in 1 product family (Developer Tools).
Key facts
- CVE ID
- CVE-2026-118746
- Severity
- Medium CVSS 6.8
- Microsoft severity
- Important
- Impact
- Security Feature Bypass
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- Weakness
- CWE-636
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- November 2026 Patch Tuesday
- Product families
- Developer Tools
CVSS score and vector
Microsoft scores CVE-2026-118746 at 6.8 (temporal 5.9) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | Required |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | None |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Not failing securely ('failing open') in .NET allows an unauthorized attacker to bypass a security feature over a network.
Frequently asked questions (Microsoft)
What kind of security feature could be bypassed by successfully exploiting this vulnerability?
The authentication feature could be bypassed as this vulnerability allows impersonation.
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
The attacker must inject themselves into the logical network path between the target and the resource requested by the victim to read or modify network communications. This is called a machine-in-the-middle (MITM) attack.
Affected products (2)
Developer Tools
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| .NET 11.0 installed on Linux | Release Notes | Security Update | 11.0.0 | |
| .NET 11.0 installed on Mac OS | Release Notes | Security Update | 11.0.0 |
NIST NVD data
- NVD status
- Awaiting Analysis
- NVD CVSS
- 6.8 (MEDIUM)
- NVD weakness
- CWE-636
- Published to NVD
- NVD last modified
References
Acknowledgments
- Alejandro Pacheco
- Anonymous
- Markus Magnuson
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. |