CVE-2026-105797: high-severity vulnerability in microsoft simplechat
SimpleChat: Command injection via authorization-gate ordering flaw (arbitrary process spawn through MCP stdio transport)
Published
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.6%
exploitation probability
0.6%top 55% of all CVEs
observed exploitation
nono source reports it
SimpleChat 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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
microsoft · simplechatRelated CVEs — microsoft simplechat
In the same product, most dangerous first.
CVE-2026-57206HIGHSimpleChat plugin validation endpoints missing authentication and authorizationEPSS 1.0%CVE-2026-57205MEDIUMSimpleChat: Authenticated users can access other users' profile metadata through user IDOR endpointsEPSS 0.9%CVE-2026-105798HIGHSimpleChat: Stored XSS via group document filename in inline onclick handlerEPSS 0.5%