CVE-2026-61459: MCP Server Kubernetes < 3.9.0 Argument Injection via kubectl Structured Tools

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-10 · updated 2026-10-25
Weakness: CWE-88

Description

MCP Server Kubernetes before 3.9.0 contains an argument injection vulnerability in structured tools (kubectl_get, kubectl_describe, kubectl_delete) that allows attackers to bypass the assertNoDangerousFlags security check by supplying resourceType and name parameters with leading dashes. Attackers can inject the --server flag to redirect kubectl commands to an attacker-controlled API server, causing the operator's bearer token to be transmitted externally and enabling full cluster compromise.

Affected products

Flux159 mcp-server-kubernetes: before 3.9.0 — fixed in 3.9.0

How to fix

Upgrade to a fixed version: Flux159 mcp-server-kubernetes 3.9.0. Check the vendor advisory for mitigations.

References

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