Deskflow is a keyboard and mouse sharing app. Prior to 1.26.0.167, a remote, unauthenticated denial of service (DoS) vulnerability affects Deskflow servers running with TLS enabled (the default). When any TCP peer connects to the listening port and its first bytes do not parse as a valid TLS ClientHello, SecureSocket::secureAccept enters its fatal-error branch and calls Arch::sleep(1) (a blocking 1-second sleep) on the multiplexer worker thread. That thread services every socket on the server, including established TLS clients delivering mouse motion, keyboard events, and clipboard updates. A single failed handshake therefore stalls input delivery to all connected screens for ~1 second, and a sustained drip of malformed connections (≥ 1/s) makes the server effectively unusable while the attack persists. This vulnerability is fixed in 1.26.0.167.

Deskflow is a keyboard and mouse sharing app. Prior to 1.26.0.138, a remote memory-safety vulnerability in Deskflow's clipboard deserialization allows a connected peer to trigger an out-of-bounds read by sending a malformed clipboard update. The issue is in the implementation of src/lib/deskflow/IClipboard.cpp. This is reachable because ClipboardChunk::assemble() in src/lib/deskflow/ClipboardChunk.cpp validates only the outer clipboard transfer size. It does not validate the internal structure of the serialized clipboard blob, so malformed inner lengths reach IClipboard::unmarshall() unchanged. This vulnerability is fixed in 1.26.0.138.

Deskflow is a keyboard and mouse sharing app. In 1.20.0, 1.26.0.134, and earlier, Deskflow daemon runs as SYSTEM and exposes an IPC named pipe with WorldAccessOption enabled. The daemon processes privileged commands without authentication, allowing any local unprivileged user to execute arbitrary commands as SYSTEM. Affects both stable v1.20.0 + and Continuous v1.26.0.134 prerelease.