CVE-2026-55157
Published:August 14, 2026
Updated:August 27, 2026
"token-optimizer-mcp" is vulnerable to OS command injection in the "smart_user" tool. The "get-user-info" operation accepts a user-controlled "username" argument and later interpolates it into a shell command executed through "execAsync()": Although the value is wrapped in double quotes, POSIX shells still evaluate command substitution such as "$(...)" and backticks inside double quotes. As a result, an MCP client can provide a crafted username such as: and execute arbitrary local commands with the privileges of the user running the MCP server. This is a CWE-78 OS command injection issue. Tested version: This issue is not related to the current "npm audit" dependency advisories. The vulnerability is in "token-optimizer-mcp"'s own tool implementation. ***
Affected Packages
https://github.com/ooples/token-optimizer-mcp.git (GITHUB):
Affected version(s) >=v5.0.0 <v5.1.0Fix Suggestion:
Update to version v5.1.0@ooples/token-optimizer-mcp (NPM):
Affected version(s) >=2.18.0 <5.1.0Fix Suggestion:
Update to version 5.1.0Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.6
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.4
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')