CVE-2026-45555: Marcelroozekrans Roslyn-Codelens-Mcp

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

Roslyn CodeLens MCP Server is a Roslyn-based MCP server providing semantic code intelligence for .NET codebases. From 0.0.9 to 1.17.0, the get_diagnostics MCP tool loads and executes all DiagnosticAnalyzer assemblies referenced by the target solution without any allowlist, signature check, or user confirmation; includeAnalyzers defaults to true, so no explicit opt-in is required. An attacker who can place a malicious .csproj referencing an attacker-controlled DLL in a location the victim opens with the MCP server will achieve arbitrary code execution in the server process with the server's OS privileges. This vulnerability is fixed in 1.17.0.

Affected products

• Marcelroozekrans Roslyn-Codelens-Mcp: from 0.0.9, before 1.17.0 (fixed in 1.17.0)

Published 2026-05-29. Last modified 2026-07-21.