---
id: CVE-2026-55156
title: >-
  Token Optimizer MCP measures token savings per AI coding agent, optimizes
  context, and shares a live local knowledge graph across 16 CLI clients
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, the dashboard HTTP server in token-optimizer-mcp exposes
  /api/sessi…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-22
vendor: ooples
product: token-optimizer-mcp
affected:
  - token-optimizer-mcp < 5.1.0
patched:
  - '@ooples/token-optimizer-mcp 5.1.0'
published: '2026-09-28'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T19:57:08.043'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55156'
references:
  - url: >-
      https://github.com/ooples/token-optimizer-mcp/commit/b4ee96dac799cbfba0a9f9c17844ce9d613cbcc7
    label: security-advisories@github.com
  - url: 'https://github.com/ooples/token-optimizer-mcp/releases/tag/v5.1.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/ooples/token-optimizer-mcp/security/advisories/GHSA-76pc-mqxp-3rq5
    label: security-advisories@github.com
  - url: >-
      https://github.com/ooples/token-optimizer-mcp/security/advisories/GHSA-76pc-mqxp-3rq5
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-76pc-mqxp-3rq5'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - npm
epss: 0.00446
epssPercentile: 0.38574
aliases:
  - GHSA-76pc-mqxp-3rq5
ecosystem: npm
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-28T18:10:48.242882Z'
ingestedAt: '2026-08-14T22:21:25.734Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55156)

Affected packages:

- `@ooples/token-optimizer-mcp < 5.1.0`

Patched in:

- `@ooples/token-optimizer-mcp 5.1.0`

Source: https://github.com/advisories/GHSA-76pc-mqxp-3rq5