SimpleChat: Command injection via authorization-gate ordering flaw (arbitrary process spawn through MCP stdio transport)

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-105797
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 15:17:16 UTC
Updated2026-10-06 18:16:47 UTC
DescriptionSimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. In versions 0.261.003 and 0.261.027, an authorization ordering flaw in POST /api/user/plugins allows an authenticated low-privileged user to omit the top-level MCP type so that _reject_non_admin_mcp_stdio skips inspection before the type is restored from metadata. The stored personal action can then reach McpPluginFactory.create_connector, and MCPStdioPlugin.connect starts the attacker-selected operating-system process under the application service identity when the action tool is invoked. Exploitation requires personal plugins to be enabled and governance to permit MCP actions, and it can expose or modify secrets and data available to the service or disrupt the service. This issue is fixed in version 0.261.031.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-78 | CWE-863 | CWE-78 CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | CWE-863 CWE-863: Incorrect Authorization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Microsoft Simplechat affected < 0.261.031 Not specified

References

ReferenceSourceLinkTags
github.com/microsoft/simplechat/commit/73ff7d6998dc4827a0f6ba002386275a7... [email protected] github.com
github.com/microsoft/simplechat/security/advisories/GHSA-h4mw-qw8m-5x4j 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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