Improper Authentication in JumpServer - CVE-2023-42818
Published: October 23, 2023 / Updated: April 27, 2026
Vulnerability identifier: #VU128131
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2023-42818
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to brute-force MFA codes.
The vulnerability exists due to improper authentication enforcement in the Koko SSH server authentication flow when handling non-compliant SSH authentication method sequences. A remote attacker can use a specially crafted SSH client to brute-force MFA codes.
The issue can be triggered by first querying public key usability with a publickey authentication request and then invoking the keyboard-interactive method.
Affected software
JumpServer
How to mitigate CVE-2023-42818
Install security update from vendor's website.
JumpServer - addressed in versions 3.5.6, 3.6.5, 3.7.2