CVE-2026-94140 Rex versions through 1.16.1 for Perl accept an unknown SSH host key for remote rsync transfers because sync hardcodes StrictHostKeyChecking=no.
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-94140?
CVE-2026-94140 is a vulnerability, published on 21 Oct 2026.
Official description
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.
Weakness: CWE-322
Which versions are affected by CVE-2026-94140?
How do I fix CVE-2026-94140?
No fix has been published for CVE-2026-94140 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-94140 being exploited?
There is no known exploitation of CVE-2026-94140 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-94140, GHSA-xx8j-qhmg-cj8f, UBUNTU-CVE-2026-94140.