# QBittorrent

qBittorrent is a cross-platform free and open-source BitTorrent client written in native C++. It relies on Boost, OpenSSL, zlib, Qt 6 toolkit and the libtorrent-rasterbar library (for the torrent back-end), with an optional search engine written in Python.

## History

qBittorrent was originally developed in March 2006 by Christophe Dumez from the University of Technology of Belfort-Montbéliard (UTBM). It is currently developed by contributors worldwide and is funded through donations, led by Sledgehammer999 from Greece, who became project maintainer in June 2013.
Along with the 4.0.0 release a new logo for the project was unveiled.
In February 2023, a security vulnerability affecting versions 4.5.0 and 4.5.1 was discovered in the Web UI running on Windows systems. This vulnerability enabled unauthenticated access to all files on the host computer via a path traversal bug. This issue has been patched in version 4.5.2, which was released to the public on February 23, 2023.
qBittorrent contained a remote code execution exploit caused by a failure to validate any TLS certificates presented to the application when downloading content via HTTP. The flaw, which had been in the application since at least 2010, was eventually fixed in version 5.0.1, on October 28, 2024, more than 14 years later. It is not believed the flaw affected downloads using the BitTorrent protocol, however the application uses HTTP(s) to check for updates, download RSS feeds and manage its Internet geolocation database.

## Features

Some of the features present in qBittorrent include:
* Bandwidth scheduler
* Bind all traffic to a specific interface
* Control over torrents, trackers and peers (torrents queueing and prioritizing and torrent content selection and prioritizing)
* DHT, PEX, encrypted connections, LPD, UPnP, NAT-PMP port forwarding support, μTP, magnet links, private torrents, v4.6.0 added (experimental) I2P support
* IP filtering: file types eMule dat or PeerGuardian
* IPv6 support
* Integrated RSS feed reader (with advanced download filters) and downloader
* Integrated torrent search engine (simultaneous search in many torrent search sites and category-specific search requests, such as books, music and software)
* Remote control through a secure web user interface
* Sequential downloading (download in order). Enables "streaming" media files
* Super-seeding option
* Torrent creation tool
* Torrent queuing, filtering and prioritizing
* Unicode support, available in ≈70 languages

## Versions

qBittorrent is cross-platform, available on many operating systems, including: FreeBSD, Linux, macOS, OS/2 (including ArcaOS and eComStation), and Windows.
As of July 2017, SourceForge statistics indicate that the most popular qBittorrent version of all supported platforms, 81% of downloads were for Windows computers.
As of May 2020, FossHub statistics indicate qBittorrent as the second most downloaded software with over 75 million downloads.
Packages for different Linux distributions are available, though most are provided through official channels via various distributions.
qBittorrent Enhanced is a fork of qBittorrent intended for blocking leeching clients such as Xunlei. It is hosted on GitHub.

## Reception

In 2012, Ghacks suggested qBittorrent as a great alternative to μTorrent, for those put off by its controversial adware and bundleware changes.
TechRadar reviewed the application in 2020, praising it for its ease of use and key features. It also pointed to its clean, ad-free interface and extensibility through plugins as features that make the software more "robust and powerful."