filezilla embeds a PuTTY client that was vulnerable: PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client) (CVE-2020-14002).
The filezilla packages are updated to fix this issue to 3.55.0 version among other bugfixes since 3.51.0 we shipped in Mageia 8. See upstream release notes for more informations.