Cyberduck and Mountain Duck improperly handle TLS certificate pinning for untrusted certificates (e.g., self-signed), unnecessarily installing it to the Windows Certificate Store of the current user without any restrictions.

This issue affects Cyberduck through 9.1.6 and Mountain Duck through 4.17.5.

Cyberduck and Mountain Duck improper handle TLS certificate pinning for untrusted certificates (e.g., self-signed), since the certificate fingerprint is stored as SHA-1, although SHA-1 is considered weak.

This issue affects Cyberduck: through 9.1.6; Mountain Duck: through 4.17.5.

Cyberduck before 4.4.4 on Windows does not properly validate X.509 certificate chains, which allows man-in-the-middle attackers to spoof FTP-SSL servers via a certificate issued by an arbitrary root Certification Authority.