Prefab UIでサーバー乗っ取りの恐れ、0.21.0で修正
Summary
Prefab UIのGenerative UIで、隔離を抜けてサーバー上でコードを実行される脆弱性が公表されました。この機能を有効にしている環境は、修正版へ更新し、サーバーの公開範囲と認証も見直してください。
AI summary
Produced by SecPulse using an external AI model; it may contain mistakes. Check the original description and references below before acting on it.
Prefab UIのGenerative UIで、隔離を抜けてサーバー上でコードを実行される脆弱性が公表されました。この機能を有効にしている環境は、修正版へ更新し、サーバーの公開範囲と認証も見直してください。
Affected packages
| Ecosystem | Package | Affected | Fixed |
|---|---|---|---|
| PrefectHQ | prefab-ui |
≥ 0.14.0, < 0.21.0 |
0.21.0 |
Original description The description as published by the source.
Prefab UI's Generative UI sandbox runs caller-supplied Python inside Pyodide, Python compiled to WebAssembly, in a Deno subprocess. The feature is documented as isolation for untrusted code, including LLM-written UI. From prefab-ui 0.14.0 through 0.20.2 the launcher starts Deno with unrestricted --allow-read, --allow-write, and --allow-net, and the runner leaves the Deno API on the JavaScript global object. Pyodide's js module proxies that global, so the Python can call Deno.readTextFileSync and Deno.writeTextFileSync. A caller who can supply the code can read and write files as the server OS user, and can persist code execution by writing a .pth file into the server virtualenv's site-packages. The usual remote path is FastMCP's GenerativeUI provider, which registers the MCP tool generate_prefab_ui and forwards that tool's code argument into this sandbox. On a FastMCP server with no authentication configured, any client who can reach the server can call the tool. With authentication, any client allowed to call tools can. Generative UI is opt-in, and the host must have Deno installed. Confirmed on prefab-ui 0.20.2. Fixed in 0.21.0: after the runtime and Prefab sources load, the runner revokes Deno read, write, and network permission before it accepts code, the process is started with --no-prompt so a permission request cannot grant them again, and bootstrap network access is limited to cdn.jsdelivr.net. The fix is commit 030f074 (pull request 538).
Source: CVE.org (CVE Program・cvelistV5) NVD GitHub Advisory
References
- advisory github.com
- advisory github.com
- advisory pypi.org
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- package pypi.org
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com
- web pypi.org
- web pypi.org
- web github.com