matrix-rust-sdk is an implementation of a Matrix client-server library in Rust. The UserIdentity::is_verified() method in the matrix-sdk-crypto crate before version 0.7.2 doesnt take into account the verification status of the users own identity while performing the check and may as a result return a value contrary to what is implied by its name and documentation. If the method is used to decide whether to perform sensitive operations towards a user identity, a malicious homeserver could manipulate the outcome in order to make the identity appear trusted. This is not a typical usage of the method, which lowers the impact. The method itself is not used inside the matrix-sdk-crypto crate. The 0.7.2 release of the matrix-sdk-crypto crate includes a fix. All users are advised to upgrade. There are no known workarounds for this vulnerability.
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.