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

> Unauthenticated attackers can bypass session authentication on the MCP endpoint to perform authenticated actions and consume API keys in server deployments.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Jun 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-j446-h28c-8p3v

## What is CVE-2026-58446?

CVE-2026-58446 is a medium-severity authentication bypass vulnerability in presenton, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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).

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-58446?


## How do I fix CVE-2026-58446?

No fix has been published for CVE-2026-58446 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58446 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58446 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-58446 and fix it if it is affected.

What it is: CVE-2026-58446 is a medium-severity authentication bypass vulnerability in presenton, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58446 exists.

Affected product: presenton. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-58446/ (Markdown: https://insights.sbomify.com/CVE-2026-58446/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58446
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58446
- OSV: https://osv.dev/vulnerability/CVE-2026-58446

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58446/
Summaries are generated and may contain mistakes; the official description above is the record.