CVE-2026-70194
published 2026-10-13CVE-2026-70194: Improper certificate validation in .NET Framework allows an unauthorized attacker to bypass a security feature over a network.
PriorityP339medium6.5CVSS 3.1
AVNACLPRNUINSUCLILAN
EPSS
0.43%
36.1th percentile
Improper certificate validation in .NET Framework allows an unauthorized attacker to bypass a security feature over a network.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | microsoft.netcore.app.runtime.linux-arm | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.linux-arm64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.linux-musl-arm | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.linux-musl-arm64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.linux-musl-x64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.linux-x64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.osx-arm64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft.netcore.app.runtime.osx-x64 | >= 11.0.0-preview.1 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| microsoft | microsoft_visual_studio_2022_version_17.14 | >= 17.14.0 < 17.14.42 | 17.14.42 |
| microsoft | microsoft_visual_studio_2026_version_18.10 | >= 18.10.0 < 18.10.4 | 18.10.4 |
| microsoft | net_11.0_runtime | >= 11.0.0 < 11.0.0-rc.2 | 11.0.0-rc.2 |
| ubuntu | dotnet10 | — | — |
| ubuntu | dotnet11 | — | — |
| ubuntu | dotnet8 | — | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
ghsa6.5MEDIUM
vendor_redhat6.5MEDIUM
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GHSA
Microsoft Security Advisory CVE-2026-70194 - .NET and Visual Studio Security Feature Bypass Vulnerability
ghsa·2026-10-13·CVSS 6.5
CVE-2026-70194 [MEDIUM] CWE-295 Microsoft Security Advisory CVE-2026-70194 - .NET and Visual Studio Security Feature Bypass Vulnerability
Microsoft Security Advisory CVE-2026-70194 - .NET and Visual Studio Security Feature Bypass Vulnerability
## Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Net.Security. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
.NET 11 post-handshake TLS client authentication can fail to verify the client certificate, allowing mutual-authentication requirements to be bypassed.
## Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/464
## CVSS Details
- **Version:** 3.1
- **Severity:** Moderate
- **Score:** 6.5
- **Vector:** `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`
- **Weakness:** CWE-295 (Im
Ubuntu
.NET vulnerabilities
vendor_ubuntu·2026-10-20
CVE-2026-70188 .NET vulnerabilities
Title: .NET vulnerabilities
Summary: Several security issues were fixed in .NET.
Multiple security issues were discovered in .NET and this update includes
new upstream .NET versions to fix these issues.
.NET 8 has been updated to 8.0.32 in Ubuntu 22.04 LTS and Ubuntu 24.04 LTS.
.NET 10 has been updated to 10.0.13 in Ubuntu 24.04 LTS, Ubuntu 26.04 LTS
and Ubuntu 26.10. .NET 11 has been updated to 11.0.0~rc2 in Ubuntu 26.10.
In addition to security fixes, the updated packages contain bug fixes, new
features, and possibly incompatible changes.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
CVE-2026-70194: Improper certificate validation in
vendor_redhat·2026-10-13·CVSS 6.5
CVE-2026-70194 [MEDIUM] CVE-2026-70194: Improper certificate validation in
Improper certificate validation in .NET Framework allows an unauthorized attacker to bypass a security feature over a network.
Package: dotnet8.0 (Red Hat Hardened Images) - Not affected
No detection rules found.
No public exploits indexed.
Sans Isc
October 2026 Microsoft Patch Tuesday, (Tue, Oct 13th)
blogs_sans_isc·2026-10-13·CVSS 8.8
CVE-2026-96951 [HIGH] October 2026 Microsoft Patch Tuesday, (Tue, Oct 13th)
October 2026 Microsoft Patch Tuesday
Published: 2026-10-13. Last Updated: 2026-10-13 19:25:52 UTC
by Johannes Ullrich (Version: 1)
0 comment(s)
Microsoft today released patches for 1,417 vulnerabilities. 76 of these vulnerabilities are rated critical, with 7 critical vulnerabiilties requiring no customer actions. One vulnerability was disclosed before today's patch Tuesday, and one is already exploited.
CVE-2026-96951: An already exploited Windows Shell Security Feature Bypass Vulnerability. This vulnerabliity allows bypassing the "Mark of the Web" making it easier to exeucte code by sending a malicious message to a user via e-mail or instant messaging. The victim will still have to open the file.
CVE-2026-108398: This vulnerability, a .NET framework security feature bypass, could be
Rapid7
Patch Tuesday - October 2026
blogs_rapid7·2026-10-13·CVSS 8.8
CVE-2026-96951 [HIGH] Patch Tuesday - October 2026
Microsoft is publishing 1,413 own-product vulnerabilities on October 2026 Patch Tuesday , including 1,102 vulnerabilities in Windows. Anyone who enjoyed last month’s record-setting Patch Tuesday will love the October 2026 edition, because it’s much bigger still. As Rapid7 has noted over the course of 2026, there is every reason to suppose that vulnerability volumes will continue to rise. Microsoft is aware of exploitation in the wild for just one of the vulnerabilities published today, as well as public disclosure for two others.
## Windows Shell: zero-day security feature bypass
The Windows Shell is Microsoft’s term for the GUI interaction logic for the entire OS provided by explorer.exe and associated libraries and APIs, and for the second time this year , the Windows Shell is the site
Bugzilla
CVE-2026-70194 dotnet: .NET Framework Security Feature Bypass Vulnerability
bugzilla·2026-10-09·CVSS 6.5
CVE-2026-70194 [MEDIUM] CVE-2026-70194 dotnet: .NET Framework Security Feature Bypass Vulnerability
CVE-2026-70194 dotnet: .NET Framework Security Feature Bypass Vulnerability
Improper certificate validation in .NET Framework allows an unauthorized attacker to bypass a security feature over a network.
Affected products:
- .NET Runtime Libraries (release 11.0): 11.0.0-preview.1 - 11.0.0-rc.1; fixed 11.0.0-rc.2
2026-10-13
Published