vulnerability / NVI-00018264 / Revision 1
MCP Server Kubernetes: Tool Access Control Bypass via Presentation-Layer Filtering Without Execution-Layer Enforcement
GitHub lists this reviewed advisory for mcp-server-kubernetes. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.8 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
mcp-server-kubernetes
source listed< 3.6.0
## Summary `mcp-server-kubernetes` exposes three environment variables (`ALLOW_ONLY_READONLY_TOOLS`, `ALLOW_ONLY_NON_DESTRUCTIVE_TOOLS`, `ALLOWED_TOOLS`) documented as access controls for restricting which Kubernetes operations are available. These controls are enforced at the tool discovery layer (`tools/list`) but not at the execution layer (`tools/call`). Any client that knows a tool name can invoke it directly regardless of the configured restriction mode. The access control was effectively cosmetic. Fixed in v3.6.0. ## Impact An attacker or misconfigured AI agent with network access to the MCP server's HTTP endpoint could invoke any Kubernetes tool regardless of the restriction mode configured by the operator -- including `kubectl_delete`, `exec_in_pod`, `kubectl_generic`, and `node_management`. The project explicitly supports and documents multi-client HTTP deployment scenarios (Streamable HTTP and SSE transports, in-cluster deployments, Codex CLI and Gemini CLI integrations). In these deployments, operators relied on the tool restriction env vars to enforce least-privilege access across users or roles. The bypass invalidated that model entirely. Severity scales with th
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-cr22-wjx7-2w6m ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.