# CVE-2025-59835: LangBot has a cross-directory file upload vulnerability, which could lead to system takeover

> Authorized attackers can upload arbitrary files to system directories via the file upload interface, potentially leading to system takeover.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Oct 2025
- **Updated:** 2 Oct 2025
- **Also known as:** GHSA-7j3j-qj83-9qv4

## What is CVE-2025-59835?

CVE-2025-59835 is a high-severity vulnerability in langbot-app LangBot, published on 2 Oct 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

LangBot is a global IM bot platform designed for LLMs. In versions 4.1.0 up to but not including 4.3.5, authorized attackers can exploit the /api/v1/files/documents interface to perform arbitrary file uploads. Since this interface does not strictly restrict the storage directory of files on the server, it is possible to upload dangerous files to specific system directories. This is fixed in version 4.3.5.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type), CWE-23 (Relative Path Traversal)

## Which versions are affected by CVE-2025-59835?


## How do I fix CVE-2025-59835?

No fix has been published for CVE-2025-59835 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-59835 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59835 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-59835 and fix it if it is affected.

What it is: CVE-2025-59835 is a high-severity vulnerability in langbot-app LangBot, published on 2 Oct 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59835 exists.

Affected product: langbot-app LangBot. 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-2025-59835/ (Markdown: https://insights.sbomify.com/CVE-2025-59835/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-59835
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-59835
- OSV: https://osv.dev/vulnerability/CVE-2025-59835

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-59835/
Summaries are generated and may contain mistakes; the official description above is the record.