CVE-2023-43652: JumpServer is an open source bastion host. As an unauthenticated user, it is possible to authenticate to the core API with a username and an SSH publi...

Description

JumpServer is an open source bastion host. As an unauthenticated user, it is possible to authenticate to the core API with a username and an SSH public key without needing a password or the corresponding SSH private key. An SSH public key should be considered public knowledge and should not used as an authentication secret alone. JumpServer provides an API for the KoKo component to validate user private key logins. This API does not verify the source of requests and will generate a personal authentication token. Given that public keys can be easily leaked, an attacker can exploit the leaked public key and username to authenticate, subsequently gaining access to the current user's information and authorized actions. This issue has been addressed in versions 2.28.20 and 3.7.1. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

0.68%

47.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Fit2cloud	Jumpserver	>= 2.0.0, < 2.28.20
Fit2cloud	Jumpserver	>= 3.0.0, < 3.7.1

References

https://github.com/jumpserver/jumpserver/security/advisories/GHSA-fr8h-xh5x-r8g9Exploit, Vendor Advisory
https://www.sonarsource.com/blog/diving-into-jumpserver-attackers-gateway-to-internal-networks-1-2Technical Description
https://github.com/jumpserver/jumpserver/security/advisories/GHSA-fr8h-xh5x-r8g9Exploit, Vendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2023-43652?

JumpServer is an open source bastion host. As an unauthenticated user, it is possible to authenticate to the core API with a username and an SSH public key without needing a password or the corresponding SSH private key. An SSH public key should be considered public knowledge and should not used as an authentication secret alone. JumpServer provides an API for the KoKo component to validate user private key logins. This API does not verify the source of requests and will generate a personal authentication token. Given that public keys can be easily leaked, an attacker can exploit the leaked public key and username to authenticate, subsequently gaining access to the current user's information and authorized actions. This issue has been addressed in versions 2.28.20 and 3.7.1. Users are advised to upgrade. There are no known workarounds for this vulnerability.

How severe is CVE-2023-43652?

CVE-2023-43652 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.68% probability of exploitation in the next 30 days.

How do I fix CVE-2023-43652?

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.