Submariner: submariner: missing validation of remote endpoint subnets and clusterid enables cross-cluster traffic hijack

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 Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption.

Source published

20 Aug 2026 18:15:06 UTC

Source modified

19 Oct 2026 17:30:24 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 8.7 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N