What’s Vulnerable › Vulnerabilities

CVE-2026-55998: Cluster Existence Oracle via Unauthenticated Import Endpoint

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-05 · updated 2026-10-24
• Weakness: CWE-204

Description

The endpoint /v3/import/{token}_{clusterId}.yaml retrieves the cluster object before validating the token. When a valid cluster ID references a cluster that has private registry secrets configured, a nil pointer dereference in pkg/systemtemplate/private_registry.go causes the request to return HTTP 502 Bad Gateway. For cluster IDs that do not exist, the endpoint returns HTTP 200. This observable difference in response codes constitutes a reliable enumeration oracle.

Affected products

• SUSE Rancher: from 2.14.0 before 2.14.4; from 2.13.0 before 2.13.8; from 2.12.0 before 2.12.12; from 2.11.0 before 2.11.16 — fixed in 2.11.16, 2.12.12, 2.13.8, 2.14.4

How to fix

Upgrade to a fixed version: SUSE Rancher 2.11.16, 2.12.12, 2.13.8, 2.14.4. Check the vendor advisory for mitigations.

References

• https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-55998
• https://github.com/rancher/rancher/security/advisories/GHSA-23h9-rr79-r3gh

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