---
issue: 113
title: "Scanner/backend: RPC response bodies read without size limit — OOM risk"
severity: medium
domain: Scanner
labels: [security, scanner, oom]
status: open
created: 2026-05-30
source: Full Codebase Audit 2026-05-30
---

# Scanner/backend: RPC response bodies read without size limit — OOM risk

**Severity:** medium
**Domain:** Scanner
**Labels:** security, scanner, oom

## Description

NB-42 applied a `LimitReader` as a mechanical guard with a default cap, but the exact byte limit per endpoint was not decided. Choosing the wrong cap (too small) breaks legitimate large responses; too large offers little protection. A malicious RPC node can still exhaust memory if the cap is too generous.

## Options

1. Wrap `resp.Body` in `io.LimitReader(resp.Body, maxBytes)` with a generous per-endpoint cap (applied as NB-42).
2. Use `http.MaxBytesReader`-style enforcement and error on exceed.
3. Stream-parse JSON with a bounded decoder.

## Recommendation

Review the default cap applied by NB-42 against actual maximum RPC response sizes for each chain (EVM batch, Tron page, TON jetton response). Adjust per-endpoint caps and error explicitly when the limit is exceeded rather than silently truncating.

## Affected Files

- `scanner/chain.go:96`
- `scanner/tron_chain.go:116`
- `scanner/ton_chain.go:106`

## References

- [Full Codebase Audit 2026-05-30](../09%20-%20Audits/Full%20Codebase%20Audit%20-%202026-05-30.md) — DEC-72
