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GHSA-6856-87HX-P5X7

Microsoft Security Advisory CVE-2026-105544 - .NET Elevation of Privilege Vulnerability

Exploited
No known exploitation
Fix
Fixed in 17.3.4, 17.8.1, 17.11.2, 17.12.1, 17.14.2, and 4 more
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 17.3.4, 17.8.1, 17.11.2, 17.12.1, 17.14.2, or one of 4 more.

Published
Last modified
Reference
Last checked
14/100 · provisional
Medium (ghsa)
None on Exploit-DB, Metasploit or GitHub

Summary

A flaw in the VSTest artifact postprocessor, which affects Microsoft.TestPlatform.CLI and the VSTest runner bundled with the .NET SDK on Windows, Linux, and macOS, lets a local user who is not the target consume a forged executionComplete.json file from another local user and run attacker-controlled output handling. The issue is an elevation of privilege flaw, so the attacker can gain higher privileges than they hold on the system.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET. This advisory provides guidance on updating affected applications and components.

The VSTest artifact postprocessor can consume a forged executionComplete.json from another local user and execute attacker-controlled output handling.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/517

CVSS Details

  • Version: 3.1
  • Severity: High
  • Score: 7.5 (base score)
  • Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
  • Weakness: CWE-284

Affected Platforms

  • Platforms: Windows, Linux, macOS
  • Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected versions of Microsoft.TestPlatform.CLI and their patched versions. The VSTest CLI is also bundled in the .NET SDK; SDK versions are listed separately below. Updating a separately installed CLI package does not replace the SDK-bundled test runner.

Microsoft.TestPlatform.CLI is affected starting with 17.2.0-preview-20220301-01, including the first stable release, 17.2.0. Use a patched version listed below for a compatible servicing line.

VSTest NuGet package

Package | Affected version | Patched version --- | --- | --- Microsoft.TestPlatform.CLI | >= 17.2.0-preview-20220301-01, < 17.3.0 | 17.3.4 Microsoft.TestPlatform.CLI | = 17.3.0 | 17.3.4 Microsoft.TestPlatform.CLI | = 17.3.1 | 17.3.4 Microsoft.TestPlatform.CLI | = 17.3.2 | 17.3.4 Microsoft.TestPlatform.CLI | = 17.3.3 | 17.3.4 Microsoft.TestPlatform.CLI | = 17.8.0 | 17.8.1 Microsoft.TestPlatform.CLI | = 17.11.0 | 17.11.2 Microsoft.TestPlatform.CLI | = 17.11.1 | 17.11.2 Microsoft.TestPlatform.CLI | = 17.12.0 | 17.12.1 Microsoft.TestPlatform.CLI | = 17.14.0 | 17.14.2 Microsoft.TestPlatform.CLI | = 17.14.1 | 17.14.2 Microsoft.TestPlatform.CLI | = 18.0.0 | 18.0.2 Microsoft.TestPlatform.CLI | = 18.0.1 | 18.0.2 Microsoft.TestPlatform.CLI | = 18.7.0 | 18.7.1 Microsoft.TestPlatform.CLI | = 18.10.0 | 18.10.2 Microsoft.TestPlatform.CLI | = 18.10.1 | 18.10.2 Microsoft.TestPlatform.CLI | = 18.11.0 | 18.11.1

Stable 18.10.1 remains affected; use Microsoft.TestPlatform.CLI 18.10.2 on that servicing line.

Other affected VSTest NuGet versions

Package | Affected version | Patched version --- | --- | --- Microsoft.TestPlatform.CLI | = 17.4.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.4.1 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.5.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.6.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.6.1 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.6.2 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.6.3 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.7.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.7.1 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.7.2 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.9.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.10.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 17.13.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.3.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.4.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.5.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.5.1 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.6.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.8.0 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.8.1 | Use a compatible patched version listed above Microsoft.TestPlatform.CLI | = 18.9.0 | Use a compatible patched version listed above

These releases have no same-line fixed package in this update. Move to a compatible fixed servicing line listed above.

Affected VSTest prerelease versions

The following table applies to Microsoft.TestPlatform.CLI.

Affected version | Patched version --- | --- = 17.3.0-preview-20220426-02 | Use a compatible patched version listed above = 17.3.0-preview-20220530-08 | Use a compatible patched version listed above = 17.3.0-preview-20220612-01 | Use a compatible patched version listed above = 17.4.0-preview-20220707-01 | Use a compatible patched version listed above = 17.4.0-preview-20220726-02 | Use a compatible patched version listed above = 17.4.0-preview-20221003-03 | Use a compatible patched version listed above = 17.4.0-release-20220926-01 | Use a compatible patched version listed above = 17.5.0-preview-20221003-04 | Use a compatible patched version listed above = 17.5.0-preview-20221221-03 | Use a compatible patched version listed above = 17.6.0-preview-20230223-05 | Use a compatible patched version listed above = 17.7.0-preview-23364-03 | Use a compatible patched version listed above = 17.7.0-preview.23280.1 | Use a compatible patched version listed above = 17.8.0-preview-23371-04 | Use a compatible patched version listed above = 17.8.0-preview-23424-02 | Use a compatible patched version listed above = 17.8.0-release-23468-02 | Use a compatible patched version listed above = 17.9.0-preview-23503-02 | Use a compatible patched version listed above = 17.9.0-preview-23531-01 | Use a compatible patched version listed above = 17.9.0-preview-23577-04 | Use a compatible patched version listed above = 17.9.0-release-23619-01 | Use a compatible patched version listed above = 17.10.0-preview-24080-01 | Use a compatible patched version listed above = 17.10.0-release-24177-07 | Use a compatible patched version listed above = 17.11.0-release-24352-06 | Use a compatible patched version listed above = 17.11.0-release-24373-02 | Use a compatible patched version listed above = 17.14.0-preview-25107-01 | Use a compatible patched version listed above

Fixed .NET SDK deliveries

Package | Affected version | Patched version --- | --- | --- .NET SDK 8.0.1xx | >= 8.0.100, <= 8.0.133 | 8.0.134 (bundled VSTest: 17.8.1-hotfix-26528-33) .NET SDK 8.0.4xx | >= 8.0.400, <= 8.0.427 | 8.0.428 (bundled VSTest: 17.11.2-hotfix-26528-32) .NET SDK 9.0.1xx | >= 9.0.100, <= 9.0.123 | 9.0.124 (bundled VSTest: 17.12.1-hotfix-26528-39) .NET SDK 9.0.3xx | >= 9.0.300, <= 9.0.320 | 9.0.321 (bundled VSTest: 17.14.2-hotfix-26528-35) .NET SDK 10.0.1xx | >= 10.0.100, <= 10.0.114 | 10.0.115 (bundled VSTest: 18.0.2-hotfix-26529-108) .NET SDK 10.0.4xx | >= 10.0.400, <= 10.0.403 | 10.0.404 (bundled VSTest: 18.7.1-hotfix-26529-119) .NET SDK 11.0.1xx | >= 11.0.100-preview.1.26104.118, <= 11.0.100-rc.3.26522.148 | 11.0.100 (bundled VSTest: 18.12.0-hotfix-26529-118)

Earlier SDKs in these serviced feature bands must be updated. The first .NET 11 general-availability SDK is fixed; its earlier preview and release-candidate SDKs require an update to 11.0.100.

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the version of Microsoft.TestPlatform.CLI used by your standalone VSTest installation.

Run dotnet --list-sdks to list installed SDKs and dotnet --version from the project directory to identify the selected SDK, including any global.json selection.

<a name="how-fix"></a>How do I fix the issue?

For standalone VSTest CLI installations, replace Microsoft.TestPlatform.CLI with its patched version listed above. For releases without a same-line fix, use a compatible fixed servicing line listed above.

Install a fixed SDK listed above and ensure test invocations select it. Updating a separately installed CLI package does not replace VSTest embedded in an older SDK.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue in the VSTest repository at https://github.com/microsoft/vstest. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-105544

Acknowledgements

  • Weeraphat Srisutham
  • Ky0toFu

Revisions

V1.0 (November 10, 2026): Advisory published.

cve.now Index

14Pcve.now Index 14 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach10/20Affects NuGet packages
  • Severity4/10Rated medium by ghsa
  • No patch0/5No signal

What would change the score

  • Would score about 69 if added to CISA KEV
  • Would score about 64 if CISA's SSVC rates exploitation active
  • Would score about 36 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

  • Upgrade to a fixed version: 17.3.4, 17.8.1, 17.11.2, 17.12.1, 17.14.2, or one of 4 more.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by GHSA-6856-87HX-P5X7 (Microsoft Security Advisory CVE-2026-105544 - .NET Elevation of Privilege Vulnerability), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for GHSA-6856-87HX-P5X7 (entry last updated 2026-11-11):
Affected:
- NuGet package Microsoft.TestPlatform.CLI: from 17.2.0-preview-20220301-01, fixed in 17.3.4
- NuGet package Microsoft.TestPlatform.CLI: from 17.3.1, fixed in 17.3.4
- NuGet package Microsoft.TestPlatform.CLI: from 17.3.2, fixed in 17.3.4
- NuGet package Microsoft.TestPlatform.CLI: from 17.3.3, fixed in 17.3.4
- NuGet package Microsoft.TestPlatform.CLI: from 17.8.0, fixed in 17.8.1
- NuGet package Microsoft.TestPlatform.CLI: from 17.11.0, fixed in 17.11.2
- NuGet package Microsoft.TestPlatform.CLI: from 17.11.1, fixed in 17.11.2
- NuGet package Microsoft.TestPlatform.CLI: from 17.12.0, fixed in 17.12.1
- NuGet package Microsoft.TestPlatform.CLI: from 17.14.0, fixed in 17.14.2
- NuGet package Microsoft.TestPlatform.CLI: from 17.14.1, fixed in 17.14.2
- and 49 more affected products, listed on https://cve.now/GHSA-6856-87HX-P5X7
Fixed versions: 17.3.4, 17.8.1, 17.11.2, 17.12.1, 17.14.2, 18.0.2, 18.7.1, 18.10.2, 18.11.1.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: GHSA-6856-87HX-P5X7 is not listed as of cve.now's last read.
This KEV status is for GHSA-6856-87HX-P5X7 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (NuGet): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://nvd.nist.gov/vuln/detail/CVE-2026-105544
- https://github.com/microsoft/vstest/security/advisories/GHSA-6856-87hx-p5x7
- https://github.com/microsoft/vstest/issues/16654
- https://github.com/dotnet/announcements/issues/517
- https://github.com/dotnet/core/blob/main/release-notes/8.0/8.0.34/8.0.34.md
- https://github.com/dotnet/core/blob/main/release-notes/9.0/9.0.23/9.0.23.md
- https://github.com/dotnet/sdk/releases/tag/v10.0.115
- https://github.com/dotnet/sdk/releases/tag/v10.0.404
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/GHSA-6856-87HX-P5X7
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id GHSA-6856-87HX-P5X7.

Timeline

  1. Advisory published
  2. Record last updated
  3. First seen by cve.now

Affected versions

Show all 59 packagesShow fewer packages

Evidence 17

Vendor advisory · 2

Establishes: Affected and fixed versions.

  1. Advisory
  2. Link

CVE record · 1

Establishes: The identifier and description.

  1. Advisory

Other links · 14

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Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about GHSA-6856-87HX-P5X7

Is GHSA-6856-87HX-P5X7 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by GHSA-6856-87HX-P5X7?

Microsoft.TestPlatform.CLI (NuGet): from 17.2.0-preview-20220301-01 before 17.3.4. Microsoft.TestPlatform.CLI (NuGet): from 17.3.1 before 17.3.4. Microsoft.TestPlatform.CLI (NuGet): from 17.3.2 before 17.3.4. Microsoft.TestPlatform.CLI (NuGet): from 17.3.3 before 17.3.4. Microsoft.TestPlatform.CLI (NuGet): from 17.8.0 before 17.8.1. 54 more packages are listed on the page.Source: cve.now feed data

How do I fix GHSA-6856-87HX-P5X7?

Upgrade to a fixed version: 17.3.4, 17.8.1, 17.11.2, 17.12.1, 17.14.2, or one of 4 more.Source: cve.now feed data

Sources

Related

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