SimpleXMQ before 3.4.0, as used in SimpleX Chat before 4.2, does not apply a key derivation function to intended data, which can interfere …

SimpleXMQ before 3.4.0, as used in SimpleX Chat before 4.2, does not apply a key derivation function to intended data, which can interfere with forward secrecy and can have other impacts if there is a compromise of a single private key. This occurs in the X3DH key exchange for the double ratchet protocol.