Arbitrary Code Execution in Roslyn CodeLens MCP Server by Vulnerable DiagnosticAnalyzer Assemblies
CVE-2026-45555

7.8HIGH

Key Information:

Vendor

Marcelroozekrans

Status
Roslyn-codelens-mcp
Vendor
CVE Published:
29 May 2026

What is CVE-2026-45555?

The Roslyn CodeLens MCP Server is susceptible to a significant security issue where the get_diagnostics MCP tool indiscriminately loads and executes DiagnosticAnalyzer assemblies from the target solution. This occurs without any validation, allowlist, or user confirmation, leading to a serious risk of arbitrary code execution if an attacker places a malicious .csproj file that references a compromised DLL within the project's accessible directories. As a result, the server operates under its OS privileges, which can lead to extensive system compromise. The vulnerability has been addressed in version 1.17.0.

Affected Version(s)

roslyn-codelens-mcp >= 0.0.9, < 1.17.0

References

https://github.com/MarcelRoozekrans/roslyn-codelens-mcp/s...
x_refsource_CONFIRM

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.