CVE-2026-58446
Presenton < 0.8.8-beta - Authentication Bypass of Session Auth via Unprotected MCP Endpoint
- State
- Published
- Severity
- 6.9 Medium
- Published
- Jun 30, 2026
- Updated
- Jul 14, 2026
- Reserved
- Jun 30, 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).
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L | VulnCheck |
Weaknesses
- CWE-306 Missing Authentication for Critical Function
Affected Products
| Product | Versions |
|---|---|
presentonpresenton |
|
References
- Release Notesrelease-notes
- Researcher Disclosuretechnical-descriptionexploit
- Maintainer PRissue-tracking
- Fix Commitpatch
- https://www.vulncheck.com/advisories/presenton-beta-authentication-bypass-of-session-auth-via-unprotected-mcp-endpointthird-party-advisory
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