CVE-2025-23390
Received Received - Intake

Fleet SSH Certificate Trust Man-in-the-Middle Vulnerability

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: SUSE

Description
A vulnerability has been identified within Fleet where, by default, Fleet will automatically trust a remote server’s certificate when connecting through SSH if the certificate isn’t set in the `known_hosts` file. This could allow the execution of a man-in-the-middle (MitM) attack against Fleet. In case the server that is being connected to has a trusted entry in the known_hosts file, then Fleet will correctly check the authenticity of the presented certificate.

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-15
AI Q&A
2026-10-15
EPSS Evaluated
N/A
NVD
CVE-2025-23390
EUVD
EUVD-2025-211104

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
SUSE fleet 0.9.0-rc.1
SUSE fleet 0.11.0
SUSE fleet 0.12.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-295 The product does not validate, or incorrectly validates, a certificate.

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Executive Summary

This vulnerability in Fleet allows it to automatically trust a remote server's SSH certificate without proper validation if the certificate is not in the known_hosts file. This creates a risk of man-in-the-middle attacks where an attacker could intercept or alter communications between Fleet and the remote server.

Detection Guidance

To detect this vulnerability, check if your Fleet version is within the affected range (>=0.9, >=0.10.0 <0.10.12, >=0.11.0 <0.11.7, >=0.12.0 <0.12.2). Verify if SSH connections to Fleet servers do not validate certificates unless entries exist in known_hosts. Inspect Fleet logs for SSH connection attempts without proper certificate checks.

Impact Analysis

This vulnerability could allow attackers to intercept sensitive data, modify communications, or impersonate legitimate servers. It may lead to unauthorized access, data breaches, or service disruption if exploited. Users of affected Fleet versions are at risk unless they upgrade to a patched version.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, which may violate compliance requirements under GDPR, HIPAA, or other regulations. It undermines data integrity and confidentiality, potentially resulting in legal penalties or loss of trust.

Mitigation Strategies

Upgrade Fleet to a patched version (0.10.12, 0.11.7, or 0.12.2 or later) immediately. Ensure all SSH connections to Fleet servers include valid entries in the known_hosts file for certificate validation. Avoid using v0.9 as it lacks a fix.

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