CVE-2026-58446
Severity CVSS v4.0:
MEDIUM
Type:
CWE-306
Missing Authentication for Critical Function
Publication date:
30/06/2026
Last modified:
14/07/2026
Description
Presenton before 0.8.8-beta bundles an MCP server that, on server/Docker deployments configured with session authentication (AUTH_USERNAME/AUTH_PASSWORD), is reachable unauthenticated at /mcp because the nginx front-end does not apply the auth_request gate to that path and the MCP server auto-mints a valid internal session token for the configured user. A remote unauthenticated attacker can invoke MCP tools such as generate_presentation, performing authenticated application actions, consuming the operators configured LLM API keys, and creating presentations in the operators instance. The Electron desktop build is not affected (MCP disabled).
Impact
Base Score 4.0
6.90
Severity 4.0
MEDIUM
Base Score 3.x
6.50
Severity 3.x
MEDIUM
References to Advisories, Solutions, and Tools
- https://github.com/presenton/presenton/commit/a1103dcef3c761cc8bab44e2862c81a49969abd7
- https://github.com/presenton/presenton/issues/678
- https://github.com/presenton/presenton/pull/679
- https://github.com/presenton/presenton/releases/tag/electron-v0.8.8-beta
- https://www.vulncheck.com/advisories/presenton-beta-authentication-bypass-of-session-auth-via-unprotected-mcp-endpoint
- https://github.com/presenton/presenton/issues/678


