CVE intelligence and bounded remediation

CVE-2023-43652 — JumpServer is an open source bastion host

Critical CVSS 9.1

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.

Severity
Critical
CVSS
9.1 (3.1)
Published
2023-09-27
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-862

Affected products

  • fit2cloud / jumpserver

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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