Cyber Resilience

CVE-2023-42818

MediumPublic PoC

Published: 27 September 2023

Published
27 September 2023
Modified
25 March 2025
KEV Added
Patch
CVSS Score v3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
EPSS Score 0.0017 38.7th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-42818 is a medium-severity Improper Authentication (CWE-287) vulnerability in Fit2Cloud Jumpserver. Its CVSS base score is 5.4 (Medium).

Operationally, ranked at the 38.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

fit2cloud
jumpserver
≤ 3.5.6 · 3.6.0 — 3.6.5

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-287 CWE-307

Requires adaptive authentication under specific conditions, directly strengthening authentication mechanisms against improper or insufficient authentication.

addresses: CWE-307

This control directly enforces limits on consecutive invalid logon attempts and automatic response (e.g., lockout) to prevent brute-force exploitation of authentication mechanisms.

addresses: CWE-287

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

References