CVE-2026-58446
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.
Does this matter?
Lower severity and a low EPSS score (0.70%). Track it; it rarely justifies an emergency change on its own.
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).
- CVSS 4.0
- 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.70% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-306
- Source
- disclosure@vulncheck.com
References
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.