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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).

PUBLISHED Reserved 2026-06-30 | Published 2026-06-30 | Updated 2026-07-14 | Assigner VulnCheck




MEDIUM: 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

MEDIUM: 6.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Problem types

Missing Authentication for Critical Function

Product status

Default status
unaffected

Any version before 0.8.8-beta
affected

Credits

George Chen finder

References

github.com/presenton/presenton/issues/678 exploit

github.com/...on/presenton/releases/tag/electron-v0.8.8-beta (Release Notes) release-notes

github.com/presenton/presenton/issues/678 (Researcher Disclosure) technical-description exploit

github.com/presenton/presenton/pull/679 (Maintainer PR) issue-tracking

github.com/...ommit/a1103dcef3c761cc8bab44e2862c81a49969abd7 (Fix Commit) patch

www.vulncheck.com/...ssion-auth-via-unprotected-mcp-endpoint third-party-advisory

cve.org (CVE-2026-58446)

nvd.nist.gov (CVE-2026-58446)

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