Juniper Networks Apstra contains a Key Exchange without Entity Authentication flaw in its SSH implementation that allows an unauthenticated attacker to perform a man-in-the-middle on the connections between Apstra and its managed devices. The lack of proper host key validation lets the attacker impersonate a managed device and capture credentials transmitted over SSH. The vulnerability is classified as CWE-322, reflecting the absence of safe authentication in the key exchange process.

The flaw affects every Apstra release prior to 6.1.1. Systems running 6.1.1 or any later release are not vulnerable. This includes all versions deployed by Juniper Networks customers for device management.

The CVSS v3.1 score of 7.0 denotes high severity, but EPSS data is not available and the issue is not listed in the CISA KEV catalog. The attack requires the ability to intercept network traffic between Apstra and its target devices; an unauthenticated attacker who can position themselves in that path can execute a MitM and impersonate the device. Because the vulnerability is network-based and does not require privileged access to Apstra, the likelihood of exploitation in exposed environments remains a significant threat.