CVE-2026-45555
Roslyn CodeLens MCP Server: Untrusted Roslyn Analyzer Execution via get_diagnostics Leads to Arbitrary Code Execution
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.
| CWE | CWE-94 |
| Vendor | marcelroozekrans |
| Product | roslyn-codelens-mcp |
| Published | May 29, 2026 |
| Last Updated | May 29, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H