Vulnerability · Published Jun 30, 2026 · Assigned by VulnCheck

CVE-2026-58446Presenton < 0.8.8-beta - Authentication Bypass of Session Auth via Unprotected MCP Endpoint

Medium 6.5

In plain English

A medium-severity missing authentication in presenton from presenton. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.7%top 46.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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).

Affected products (as reported)

Vendor	Product	Versions
presenton	presenton	0 – before 0.8.8-beta

Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

References

Release Notes release-notes
Researcher Disclosure technical-description, exploit
Maintainer PR issue-tracking
Fix Commit patch
https://www.vulncheck.com/advisories/presenton-beta-authentication-bypass-of-session-auth-via-unprotected-mcp-endpoint third-party-advisory