Live › vulnerability › CVE-2026-94140
Go to dashboardRex through version 1.16.1 runs rsync over SSH with StrictHostKeyChecking=no hardcoded, so it accepts any host key for remote sync transfers. An attacker who can redirect the connection can capture the password sent under password authentication and read or write the transferred files.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Teams that use Rex's sync function to move files to or from remote hosts over SSH are affected, especially with password authentication, where the password is sent to whichever server answers. Exposure depends on an attacker being able to redirect the connection before the real host key is known, such as on an untrusted network or through DNS or routing manipulation. Teams that only run local tasks or do not use sync can skip it.
No product ranges from the sources yet.
perl -MRex -e 'print $Rex::VERSION' or cpanm --info Rexsync calls to remote hosts and for set_openssh_opt, since the option does not reach the rsync transport1.16.1 once a fixed release is published (unknown from the sources)sync over untrusted networks and do not use password authentication for itEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
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.
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