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CVE-2025-71261 — Vulnerability in github.com/harvester/harvester —...

HIGH

Harvester's SUSE Virtualization Registration Client Vulnerable to MITM and DOS

Published May 6, 2026Updated September 10, 2026Source: osv

Summary

### 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://attack.mitre.org/techniques/T1499/004/) for further information about this category of attack. ### Patches This vulnerability is addressed by updating the registration client’s default behaviour to validate the certificate presented by the remote server against the list of trusted system root certificate authority (CA) and those defined by the `additional-ca` setting. Patched versions of SUSE Virtualization include releases v1.8.0 or newer. ### Workarounds If developers can't upgrade to a fixed version, ensure that only authorized cluster administrators can access and modify the `cluster-registration-url` setting. ### Resources If there are any questions or comments about this advisory: * Reach out to the [SUSE Rancher Security team](https://github.com/rancher/rancher/security/policy) for security related inquiries. * Open an issue in the [Rancher](https://github.com/rancher/rancher/issues/new/choose) repository. * Verify with SUSE [support matrix](https://www.suse.com/suse-rancher/support-matrix/all-supported-versions/) and [product support lifecycle](https://www.suse.com/lifecycle/).

Advisory Timeline

  • First published May 6, 2026 (159 days ago).
  • Last revised September 10, 2026 — 126 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Go
Update github.com/harvester/harvester to 1.8.0 or later
go get github.com/harvester/harvester@v1.8.0

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Affects 1 ecosystem: go (1).

PackageEcosystemAffectedFixed In
github.com/harvester/harvester
go
All versions1.8.0

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

  • CWE-295
    Improper Certificate ValidationMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 8.6 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Frequently Asked Questions

What is CVE-2025-71261?
Harvester's SUSE Virtualization Registration Client Vulnerable to MITM and DOS This vulnerability has been assigned a severity rating of HIGH (CVSS score: 8.6/10).
How do I check if my project is affected by CVE-2025-71261?
CVE-2025-71261 affects github.com/harvester/harvester. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2025-71261 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
8.6

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-pgh9-mpwc-8jjf
GO-2026-5538

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  • CVE-2026-107813
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    Nginx UI: Incomplete fix of CVE-2026-84315 - the api/cluster router was not - wrapped in RequireSecureSession, so those sensitive mutations run without OTP step-up

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