Improper Certificate Validation in Microsoft .NET Framework components

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2018-0786: 3.69% estimated exploitation activity in the next 30 days; percentile 89.71 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Microsoft .NET Framework 2.0 SP2, 3.0 SP2, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, .NET Core 1.0 and 2.0, and PowerShell Core 6.0.0 allow a security feature bypass vulnerability due to the way certificates are validated, aka ".NET Security Feature Bypass Vulnerability."

Published by the source

16 Oct 2018, 19:59 UTC

Last modified by the source

29 Jan 2023, 05:05 UTC

Source last checked

26 Oct 2026, 16:58 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jc8g-xhw5-6x46

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# Patch Next advisory brief: CVE-2018-0786

Advisory: Improper Certificate Validation in Microsoft .NET Framework components
IDs: CVE-2018-0786, GHSA-jc8g-xhw5-6x46
Record: https://patchnext.com/advisories/cve-2018-0786 (revision 1, source checked 26 Oct 2026, 16:58 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: system.servicemodel.duplex 4.4.1, 4.3.1, 4.0.2; microsoft.netcore.universalwindowsplatform 6.0.6, 5.4.2, 5.3.5, 5.2.4; system.servicemodel.primitives 4.4.1, 4.3.1, 4.1.1; system.servicemodel.http 4.4.1, 4.3.1, 4.1.1; system.servicemodel.security 4.4.1, 4.3.1, 4.0.2; system.servicemodel.nettcp 4.4.1, 4.3.1, 4.1.1; system.private.servicemodel 4.4.1, 4.3.1, 4.1.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet system.servicemodel.duplex: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.0.1, <= 4.0.1; fixed in 4.4.1, 4.3.1, 4.0.2
- NuGet microsoft.netcore.universalwindowsplatform: affected >= 5.2.0, < 5.2.4; >= 5.3.0, < 5.3.5; >= 5.4.0, < 5.4.2; >= 6.0.0, < 6.0.6; fixed in 5.4.2, 5.2.4, 6.0.6, 5.3.5
- NuGet system.servicemodel.primitives: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.1.0, <= 4.1.0; fixed in 4.4.1, 4.3.1, 4.1.1
- NuGet system.servicemodel.http: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.1.0, <= 4.1.0; fixed in 4.4.1, 4.3.1, 4.1.1
- NuGet system.servicemodel.security: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.0.1, <= 4.0.1; fixed in 4.4.1, 4.3.1, 4.0.2
- NuGet system.servicemodel.nettcp: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.1.0, <= 4.1.0; fixed in 4.4.1, 4.3.1, 4.1.1
- NuGet system.private.servicemodel: affected >= 4.4.0, <= 4.4.0; >= 4.3.0, <= 4.3.0; >= 4.1.0, <= 4.1.0; fixed in 4.4.1, 4.3.1, 4.1.1

## Suggested inspection (read-only)
- NuGet system.servicemodel.duplex: check the installed version with your package manager.
- NuGet microsoft.netcore.universalwindowsplatform: check the installed version with your package manager.
- NuGet system.servicemodel.primitives: check the installed version with your package manager.
- NuGet system.servicemodel.http: check the installed version with your package manager.
- NuGet system.servicemodel.security: check the installed version with your package manager.
- NuGet system.servicemodel.nettcp: check the installed version with your package manager.
- NuGet system.private.servicemodel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on system.servicemodel.duplex, microsoft.netcore.universalwindowsplatform, system.servicemodel.primitives, system.servicemodel.http, system.servicemodel.security, system.servicemodel.nettcp, system.private.servicemodel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jc8g-xhw5-6x46 (GitHub-reviewed advisory GHSA-jc8g-xhw5-6x46 lists affected ranges: NuGet microsoft.netcore.universalwindowsplatform >=5.2.0 =5.3.0 =5.4.0 =6.0.0 =4.4.0 =4.3.0 =4.1.0 =4.4.0 =4.3.0 =4.1.0 =4.4.0 =4.3.0 =4.1.0 =4.4.0 =4.3.0…)

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