CVE-2026-55157

Token Optimizer MCP: OS command injection in smart_user via username in get-user-info

HIGH
8.4
CVSS Score
Published: September 28, 2026 at 05:48 PM UTC
Updated: October 1, 2026 at 03:17 PM UTC
1 product affected across 1 vendorToken Optimizer Mcp

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Severity
HIGH8.4
Exploit prediction
EPSS 0.9%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.1.0
Affected range stops below 5.1.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.4HIGHGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-78

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