Cluster Existence Oracle via Unauthenticated Import Endpoint

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55998
StatePUBLISHED
Assignersuse
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 08:16:34 UTC
Updated2026-08-05 14:17:08 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

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

EPSS: 0.002050000 probability, percentile 0.106540000 (date 2026-08-07)

Problem Types: CWE-204 | CWE-204 CWE-204 Observable response discrepancy

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNACVSS5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA SUSE Rancher affected 2.14.0 2.14.4 semver Not specified
CNA SUSE Rancher affected 2.13.0 2.13.8 semver Not specified
CNA SUSE Rancher affected 2.12.0 2.12.12 semver Not specified
CNA SUSE Rancher affected 2.11.0 2.11.16 semver Not specified

References

ReferenceSourceLinkTags
bugzilla.suse.com/show_bug.cgi [email protected] bugzilla.suse.com
github.com/rancher/rancher/security/advisories/GHSA-23h9-rr79-r3gh [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: This vulnerability was discovered and reported by Michael Wollner (@ibonok) from Deutsche Telekom AG. (en)

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