Technical impact
Kyverno is a cloud-native policy engine whose policy engine can consume unbounded memory when evaluating policies that use context variables to exponentially amplify string data. This flaw, identified as a resource-consumption vulnerability (CWE-770), enables a privileged user who can create policies to cause the host running Kyverno to run out of memory and become unresponsive, resulting in a denial of service. The impact is limited to the system where Kyverno runs, but the high memory consumption can affect other containers and services on the same node.
Affected Systems
The vulnerability affects Kyverno versions prior to 1.16.3 and 1.15.3. The affected vendor is Kyverno, product Kyverno, any installation that uses the vulnerable policy engine component.
Risk and Exploitability
The CVSS score is 7.7, indicating a high severity, while the EPSS score is below one percent, suggesting a low probability of exploitation in the wild. The vulnerability is not listed in the KEV catalog, meaning no confirmed public exploits are available. Attackers need policy-creation privileges, which are typically held by administrators or service accounts; therefore, the attack vector is internal or privileged. The primary risk is a DoS of the Kyverno service and potentially other workloads sharing the node if memory is exhausted. Prompt patching reduces the attack surface, and limiting privileges further mitigates risk.
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