CVE-2023-42818: FIT2CLOUD Jumpserver

Critical severity, CVSS 9.8. EPSS: 0.7% chance of exploitation in the next 30 days.

JumpServer is an open source bastion host. When users enable MFA and use a public key for authentication, the Koko SSH server does not verify the corresponding SSH private key. An attacker could exploit a vulnerability by utilizing a disclosed public key to attempt brute-force authentication against the SSH service This issue has been patched in versions 3.6.5 and 3.5.6. Users are advised to upgrade. There are no known workarounds for this issue.

Affected products

• FIT2CLOUD Jumpserver: before 3.5.6 (fixed in 3.5.6); from 3.6.0, before 3.6.5 (fixed in 3.6.5)

Published 2023-09-27. Last modified 2026-06-17.