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

Published Oct 21, 2026 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

No fixed CPAN release is currently available.

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History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Rex versions through 1.16.1 for Perl accept an unknown SSH host key for remote rsync transfers because sync hardcodes StrictHostKeyChecking=no
Weaknesses CWE-322
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Weaknesses

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Status
PUBLISHED
Assigner
CPANSec
Published
Updated
Oct 30, 2026, 3:52 PM
Reserved
Sep 20, 2026, 7:46 PM
Status
Awaiting Analysis
Published
Oct 21, 2026, 10:16 PM
Modified
Oct 30, 2026, 4:18 PM