TI-2026-39845 Aliases CVE-2026-55156 GHSA-76pc-mqxp-3rq5

Token Optimizer MCP: Unauthenticated Path Traversal in Dashboard Session Log API Endpoints

MEDIUM 63CWE-22Published 2026-09-28 · Updated 2026-09-28

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Information disclosure
Confidentiality · integrity · availability: Low · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-22 and the CVSS impact.

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/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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00446 38th percentileScored 2026-11-07

Fix Fixed token-optimizer-mcp (ooples): 5.1.0@ooples/token-optimizer-mcp (npm): 5.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
ooples	token-optimizer-mcp	before 5.1.0	5.1.0	Patch available	CNA
—	@ooples/token-optimizer-mcp (npm)	before 5.1.0	5.1.0	Patch available	GHSA-76pc-mqxp-3rq5

token-optimizer-mcp Vendorooples Affected before 5.1.0 Fixed in 5.1.0 Patch available CNA
@ooples/token-optimizer-mcp (npm) Vendor— Affected before 5.1.0 Fixed in 5.1.0 Patch available GHSA-76pc-mqxp-3rq5

Remediation

Fix · CNA token-optimizer-mcp (ooples) Fixed in 5.1.0
Fix · GHSA-76pc-mqxp-3rq5 @ooples/token-optimizer-mcp (npm) Fixed in 5.1.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-55156
2026-10-03 Alias added: GHSA-76pc-mqxp-3rq5

References

Other 4

TI-2026-39846 Token Optimizer MCP: OS command injection in smart_user via username in get-user-info CVSS 3.1HIGH 8.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences