Draft in the CWE catalog · 33 CVEs mapped
The product performs a key exchange with an actor without verifying the identity of that actor.
Net::LibSSH versions before 0.004 for Perl authenticate to an unverified server because connect never checks the host key against known_hosts. connect reports success as soon as ssh_connect returns SSH_OK. libssh leaves the known-hosts check to the application, and this binding never makes it, so the strict_hostkeycheck and knownhosts options are set on the session and then decide nothing. Password, agent and public-key authentication, channel and SFTP operations all run on a session whose peer was never identified, so an attacker who can redirect the connection receives the password when password authentication is used, and commands and data sent over the session.
Rex versions through 1.16.1 for Perl accept an unknown SSH host key for remote rsync transfers because sync hardcodes StrictHostKeyChecking=no. Every remote branch of sync builds its ssh command with that option, for password authentication, for private-key authentication and for the fallback. The ssh options a caller sets through set_openssh_opt reach the OpenSSH transport but not this command, so there is no configuration that restores host key checking for the transfer. An attacker who can redirect the connection before the real host key is known presents their own and the transfer proceeds: under password authentication sync sends the connection password to that server, an upload writes the selected local files to it, and a download writes what it returns to the local destination.
The Apache Airflow SFTP provider's deferrable code paths (`SFTPTrigger`, `SFTPHookAsync`, `SFTPClientPool`) disable SSH host-key verification by default unless the connection explicitly sets `no_host_key_check` to false. Deployments that run SFTP sensors or operators in deferrable mode are affected. An attacker in a machine-in-the-middle position between the triggerer and the SFTP server can impersonate the server and capture the credentials or data exchanged. Users of apache-airflow-providers-sftp are recommended to upgrade to apache-airflow-providers-sftp 7.0.0 or later. This is a separate defect from CVE-2026-94134 (the synchronous SSH hook default, which also affects the SFTP hook); users who applied the fix for one also need this release for the other - apache-airflow-providers-sftp 7.0.0 fixes both.