Research NoteSeptember 9, 20253 min read
Wazero Memory Allocation Bounds
Hard limits on sandbox memory footprints.
Problem
A rogue or poorly optimized policy executed inside the WebAssembly sandbox might allocate memory indiscriminately. Left unchecked, the host OS's OOM killer will terminate the entire node, resulting in total system failure.
Approach
Under the HELM Wazero configuration, linear memory pages are strictly pre-allocated. We define a hard 16MB limit for standard policy evaluations. Wazero intercepts dynamic allocation requests (e.g., memory.grow); if the limit is breached, the trap immediately suspends the WebAssembly instance.
Invariants
- The Sandbox instance cannot dynamically exceed
16 * 1024 * 1024bytes. - Memory allocation faults evaluate as
DENY_EXHAUSTION.
Artifacts
References
- WebAssembly Core Specification: Linear Memory
Pesquisa Mindburn Labs • September 9, 2025