What is CVE-2026-55156?

CVE-2026-55156 is a medium-severity vulnerability in Ooples Token-Optimizer-Mcp, classified under Path Traversal. CVSS score: 5.3/10. Published 2026-09-28.

How severe is CVE-2026-55156?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Path Traversal in Ooples Token-Optimizer-Mcp

CVE-2026-55156

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.

Vulnerability class: Path Traversal (Directory Traversal)

Published 2026-09-28 · last modified 2026-09-28.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Ooples Token-Optimizer-Mcp — versions < 5.1.0

Weakness classification (CWE)

CWE-22 — Path Traversal

References

Frequently asked questions

What is CVE-2026-55156?: CVE-2026-55156 is a medium-severity vulnerability in Ooples Token-Optimizer-Mcp, classified under Path Traversal. CVSS score: 5.3/10. Published 2026-09-28.
How severe is CVE-2026-55156?: Medium severity. CVSS v3 base score is 5.3 out of 10.