CVE-2025-71261 — harvester
HIGHCVE-2025-71261 is a high-severity (CVSS 8.6) remote code execution vulnerability in github.com/harvester/harvester. A fix is available for github.com/harvester/harvester — see the affected versions and patch details below.
Harvester's SUSE Virtualization Registration Client Vulnerable to MITM and DOS
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-71261.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2025-71261 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/harvester/harvesterReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A vulnerability has been identified in the SUSE Virtualization (Harvester) Rancher integration mechanism 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 and MITRE ATT&CK - Technique - Endpoint Denial of Service: Application or System Exploitation 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 for security related inquiries.
- Open an issue in the Rancher repository.
- Verify with SUSE support matrix and product support lifecycle.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/harvester/harvester | all versions | 1.8.0go get github.com/harvester/harvester@v1.8.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/harvester/harvester, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/harvester/harvester to 1.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-71261 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Frequently Asked Questions
Is CVE-2025-71261 in your dependencies?
Find it across Go, including transitive dependencies.