nemu_set_vtable_slot
Override a specific vtable slot with a custom host function. The slot at vtableAddr + slotIndex*8 is rewritten to point to a stub executing
This record as markdown: /tools/io-github-vmoranv-jshookmcp/nemu-set-vtable-slot.md
What nemu_set_vtable_slot does on Jshookmcp
AI agents invoke nemu_set_vtable_slot to trigger actions in Jshookmcp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why nemu_set_vtable_slot is rated High
Overwrites function pointers in memory, enabling arbitrary code execution via vtable manipulation.
From the tool's definition Override vtable slot, rewritten to point to stub executing
Attacks that exploit this kind of access
The rule that runs nemu_set_vtable_slot safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For nemu_set_vtable_slot, this is the rule to start with:
nemu_set_vtable_slot stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Jshookmcp, apply this rule, and every nemu_set_vtable_slot call is checked against it from then on.
Questions about nemu_set_vtable_slot
Override a specific vtable slot with a custom host function. The slot at vtableAddr + slotIndex*8 is rewritten to point to a stub executing. It is categorised as a Execute tool in the Jshookmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Jshook MCP server in PolicyLayer and add a rule for nemu_set_vtable_slot: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Jshookmcp. Nothing to install.
nemu_set_vtable_slot is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the nemu_set_vtable_slot rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for nemu_set_vtable_slot. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
nemu_set_vtable_slot is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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