qBittorrent before 5.0.1 proceeds with use of https URLs even after certificate validation errors.

All versions of the qBittorrent client through 4.5.5 use default credentials when the web user interface is enabled. The administrator is not forced to change the default credentials. As of 4.5.5, this issue has not been fixed. A remote attacker can use the default credentials to authenticate and execute arbitrary operating system commands using the "external program" feature in the web user interface. This was reportedly exploited in the wild in March 2023.

In qBittorrent before 4.1.7, the function Application::runExternalProgram() located in app/application.cpp allows command injection via shell metacharacters in the torrent name parameter or current tracker parameter, as demonstrated by remote command execution via a crafted name within an RSS feed.

The UI Lock feature in qBittorrent version 3.3.15 is vulnerable to Authentication Bypass, which allows Attack to gain unauthorized access to qBittorrent functions by tampering the affected flag value of the config file at the C:\Users\<username>\Roaming\qBittorrent pathname. The attacker must change the value of the "locked" attribute to "false" within the "Locking" stanza. NOTE: This is an intended behavior. See https://github.com/qbittorrent/qBittorrent/wiki/I-forgot-my-UI-lock-password

In Vuze Bittorrent Client 5.7.6.0, the XML parsing engine for SSDP/UPnP functionality is vulnerable to an XML External Entity Processing (XXE) attack. Remote, unauthenticated attackers can use this vulnerability to: (1) Access arbitrary files from the filesystem with the same permission as the user account running Vuze, (2) Initiate SMB connections to capture a NetNTLM challenge/response and crack to cleartext password, or (3) Initiate SMB connections to relay a NetNTLM challenge/response and achieve Remote Command Execution in Windows domains.

A security issue was found in bittorrent-dht before 5.1.3 that allows someone to send a specific series of messages to a listening peer and get it to reveal internal memory.

WebUI in qBittorrent before 3.3.11 did not escape many values, which could potentially lead to XSS.

WebUI in qBittorrent before 3.3.11 did not set the X-Frame-Options header, which could potentially lead to clickjacking.

BitTorrent and uTorrent allow remote attackers to inject command line parameters and execute arbitrary commands via a crafted URL using the (1) bittorrent or (2) magnet protocol.

The web interface in BitTorrent allows remote attackers to execute arbitrary commands by leveraging knowledge of the pairing values and a crafted request to port 10000.