The remote SSH server is vulnerable to a mitm prefix truncation attack.
"The remote SSH server is vulnerable to a man-in-the-middle prefix truncation weakness known as Terrapin. This can allow a remote, man-in-the-middle attacker to bypass integrity checks and downgrade the connection's security. Note that this plugin only checks for remote SSH servers that support either ChaCha20-Poly1305 or CBC with Encrypt-then-MAC and do not support the strict key exchange countermeasures. It does not check for vulnerable software versions."
Contact the vendor for an update with the strict key exchange countermeasures or disable the affected algorithms. CVE-2023-48795
Is DX NetOps Spectrum impacted by this vulnerability?
DX NetOps Spectrum releases 23.3.5 and older
Spectrum uses JSCH 0.1.55 which is vulnerable.