Medium
Cluster Existence Oracle via Unauthenticated Import Endpoint
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-55998
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 8 Nov 2026, 02:46 UTC · Revision 1
Source evidence
Cluster Existence Oracle via Unauthenticated Import Endpoint
core-osv · Original sourcePublished 5 Aug 2026, 07:51 UTC
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.
osv:CVE-2026-55998
Complete source record
{
"id": "e25198b0519d576179d39219cd749f6b94dd8698a94ed33e6c3eba0345c59264",
"url": "https://osv.dev/vulnerability/CVE-2026-55998",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Cluster Existence Oracle via Unauthenticated Import Endpoint",
"summary": "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.",
"evidence": "osv:CVE-2026-55998",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-55998",
"aliases": [
"CVE-2026-55998",
"GHSA-23h9-rr79-r3gh"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
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{
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"type": "GIT",
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{
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{
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55998.json"
}
}
],
"modified": "2026-10-28T02:30:53.023385168Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55998.json",
"https://github.com/rancher/rancher/security/advisories/GHSA-23h9-rr79-r3gh",
"https://nvd.nist.gov/vuln/detail/CVE-2026-55998",
"https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-55998"
],
"provider_metadata": {
"cwe_ids": [
"CWE-204"
],
"cna_assigner": "suse",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55998.json"
}
},
"related_cves": [
{
"value": "CVE-2026-55998",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 521916,
"published_at": "2026-08-05T07:51:21.731+00:00"
}