Junglewise Threat Intelligence

CVE-2026-58446: Presenton authentication bypass in MCP server endpoint

CVE-2026-58446 · Severity: medium · CVSS 6.5 · Published 2026-06-30

Executive brief

Presenton, an AI-powered presentation tool, contains a security flaw in its server and Docker deployments. An attacker can bypass login requirements to access the internal Model Context Protocol (MCP) server. This allows unauthorized individuals to generate presentations and use the owner's paid AI credits (LLM API keys) without permission.

Technical details

An authentication bypass exists in Presenton's server/Docker deployments due to a misconfiguration in the Nginx front-end. While the application uses AUTH_USERNAME/AUTH_PASSWORD for session authentication, the Nginx configuration fails to apply the 'auth_request' gate to the /mcp path. Furthermore, the MCP server component automatically generates a valid internal session token for the configured user upon access. A remote, unauthenticated attacker can exploit this to invoke MCP tools like 'generate_presentation', effectively performing actions as an authenticated user and consuming configured LLM API keys. This issue was resolved in version 0.8.8-beta by implementing mandatory bearer token authentication for all MCP endpoints.

Affected products

  • Presenton Presenton before 0.8.8-beta

Timeline

  • 2026-06-17: patched: Fix committed to main branch
  • 2026-06-18: advisory: Release 0.8.8-beta published
  • 2026-06-30: disclosed: CVE-2026-58446 published

References