Medium severity · published Oct 15, 2026
CVE-2025-23390
Fleet doesn’t validate a server’s certificate when connecting through SSH
6.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 9% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FL
fleet · SUSE
0.9.0-rc.1 before 0.10.12; 0.11.0 before 0.11.7; 0.12.0 before 0.12.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-23390
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-23390
bugzilla.suse.com
https://bugzilla.suse.com/show_bug.cgi?id=CVE-2025-23390
github.com
https://github.com/rancher/fleet/security/advisories/GHSA-xgpc-q899-67p8
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