Harvester's SUSE Virtualization Registration Client Vulnerable to MITM and DOS
Date: 2026-05
Affected: go/github.com/harvester/harvester
Attack vector: deepfake
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2025-71261
CWE: CWE-295
CVSS: 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H)

### Impact A vulnerability has been identified in the [SUSE Virtualization (Harvester) Rancher integration mechanism](https://docs.harvesterhci.io/v1.7/rancher/rancher-integration) where by default the registration client uses an insecure TLS option that fails to verify the remote server’s certificate. This security gap could allow the execution of a man-in-the-middle (MitM) attack against SUSE Virtualization. An attacker with network-level access between the SUSE Virtualization and Rancher Manager could interfere with the TLS handshake and abuse it to bypass TLS as a security control. The registration client could be misled to send cluster registration requests to an impersonated remote service. Additionally, because the system processes response payloads without performing size validation, an attacker could induce a memory buffer overflow, leading to a potential crash of the SUSE Virtualization registration controller. Note that this vulnerability only affects the cluster registration configuration (the `cluster-registration-url` setting) which is distinct from the secured configuration used to maintain operational connectivity between SUSE Virtualization and Rancher Manager, as well as between the manager and hosted downstream clusters. Please consult the associated[ MITRE ATT&CK - Technique - Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557/) and [MITRE ATT&CK - Technique - Endpoint Denial of Service: Application or System Exploitation](https://atta


Mitigations:

Architectural layers (MAESTRO):