CVE-2023-42818

Name: CVE-2023-42818
Creator: NVD / NIST
Published: 2023-09-27T21:15:10.173+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.58%

Last modified Jun 17, 2026

CVE-2023-42818 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.58% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.58%

43.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Fit2cloud	Jumpserver	< 3.5.6
Fit2cloud	Jumpserver	>= 3.6.0, < 3.6.5

References

https://github.com/jumpserver/jumpserver/security/advisories/GHSA-jv3c-27cv-w8jvExploit, Vendor Advisory
https://www.sonarsource.com/blog/diving-into-jumpserver-attackers-gateway-to-internal-networks-1-2
https://github.com/jumpserver/jumpserver/security/advisories/GHSA-jv3c-27cv-w8jvExploit, Vendor Advisory

Timeline

Published: Sep 27, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-42818?

How severe is CVE-2023-42818?

CVE-2023-42818 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.

How do I fix CVE-2023-42818?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-42818?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST