Multicluster-global-hub: multicluster-global-hub: spec-topic read acl leaks bootstrap kubeconfigs to all managed hubs during migration

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

A flaw was found in multicluster-global-hub. During a ManagedClusterMigration, the system incorrectly grants all managed hubs read access to a shared communication topic. This allows a compromised managed hub to intercept and collect sensitive bootstrap kubeconfigs, which contain API server tokens intended for other hubs. These tokens have an extended validity of approximately 9.86 years, significantly increasing the risk of unauthorized access and information disclosure to other managed clusters.

Source published

10 Aug 2026 16:43:20 UTC

Source modified

29 Sep 2026 17:21:47 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 6.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N