# CVE-2026-50158: yutu: Arbitrary File Write via MCP `caption-download` Tool

> Attackers can write arbitrary files via the caption-download tool, potentially overwriting critical files to achieve code execution or denial of service.

- **Severity:** High 7.7 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** GHSA-2c7f-fxww-6w6c, GO-2026-5980

## What is CVE-2026-50158?

CVE-2026-50158 is a high-severity path traversal vulnerability in eat-pray-ai yutu, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

yutu is an AI-powered toolkit for managing and growing YouTube channels. Prior to 0.10.9, the caption-download MCP tool accepts a caller-controlled file parameter through cmd/caption/download.go and passes it to Caption.Download() in pkg/caption/caption.go, where os.Create() creates or truncates that path without using the pkg.Root confinement boundary backed by YUTU_ROOT. A principal able to invoke caption-download, including a local HTTP client when the MCP server runs with its default authentication-disabled configuration, can write downloaded caption bytes to any path writable by the yutu process outside YUTU_ROOT. This can overwrite application files, configuration, shell startup files, logs, or data and can cause persistent code execution or denial of service depending on the selected writable target. Live caption retrieval also requires usable service credentials and an accessible caption identifier. This issue is fixed in version 0.10.9.

Weakness: CWE-73 (External Control of File Name or Path)

## Which versions are affected by CVE-2026-50158?

3 open source packages ship an affected version, including github.com/eat-pray-ai/yutu.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/eat-pray-ai/yutu` | Go | All versions | 0.10.9-dev1 |
| `github.com/eat-pray-ai/yutu` | Go | All versions | 0.10.9-dev1 |
| `github.com/eat-pray-ai/yutu` | Go | All versions | 0.10.9-dev1 |

## How do I fix CVE-2026-50158?

Upgrade github.com/eat-pray-ai/yutu to 0.10.9-dev1 or later.

## Is CVE-2026-50158 being exploited?

There is no known exploitation of CVE-2026-50158 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50158 and fix it if it is affected.

What it is: CVE-2026-50158 is a high-severity path traversal vulnerability in eat-pray-ai yutu, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-50158 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/eat-pray-ai/yutu (Go): affected all versions; fixed in 0.10.9-dev1
- github.com/eat-pray-ai/yutu (Go): affected all versions; fixed in 0.10.9-dev1
- github.com/eat-pray-ai/yutu (Go): affected all versions; fixed in 0.10.9-dev1

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-2026-50158/ (Markdown: https://insights.sbomify.com/CVE-2026-50158/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50158
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50158
- OSV: https://osv.dev/vulnerability/CVE-2026-50158

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50158/
Summaries are generated and may contain mistakes; the official description above is the record.