CVE-2026-55157

HighCVSS 8.4

Published: 28/09/2026(UTC)Updated: 01/10/2026(UTC)Translated: 29/09/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Elevated risk

0.71%

52th percentile - higher than 52% of all known CVEs

Summary

Token Optimizer MCP measures token savings per AI coding agent, optimizes context, and shares a live local knowledge graph across 16 CLI clients. Prior to version 5.1.0, token-optimizer-mcp is vulnerable to OS command injection in the smart_user tool. Any MCP client that can call the smart_user tool can execute arbitrary shell commands through the username argument of the get-user-info operation. The commands execute with the privileges of the user running the token-optimizer-mcp server. This issue has been patched in version 5.1.0.

Risk Assessment

The risk includes the ability for an MCP client to execute arbitrary commands on the server, potentially leading to system compromise, data theft, or service disruption.

Recommendation

Update token-optimizer-mcp to version 5.1.0 or later and restrict access to the smart_user tool to trusted clients only.

Other vulnerabilities in token-optimizer-mcp

CVE-2026-55156Medium
Token Optimizer MCP measures token savings per AI coding agent, optimizes context, and shares a live local knowledge graph across 16 CLI clients. Prior to version 5.1.0, the dashboard HTTP server in token-optimizer-mcp exposes /api/session-summary and /api/session-events with no authentication middleware — any network-accessible client can reach them without credentials. Both handlers concatenate the caller-supplied sessionId query parameter directly into a filesystem path via path.join, and Node.js normalizes .. segments at resolution time, allowing an unauthenticated attacker to read any .jsonl file reachable from the server's filesystem. This issue has been patched in version 5.1.0.

Original NVD description (English source)

Vulnerability data from NVD (NIST) · CISA KEV · EPSS