GHSA-9vqf-7f2p-gf9v Hono: bodyLimit() can be bypassed for chunked / unknown-length requests

• npm hono: < 4.12.16 → fixed in 4.12.16

Summary `bodyLimit()` does not reliably enforce `maxSize` for requests without a usable `Content-Length` (e.g. `Transfer-Encoding: chunked`). Oversized requests can reach handlers and return `200` instead of `413`. Details For chunked / unknown-length requests, `bodyLimit()` wraps the body in a stream that counts bytes asynchronously, then runs the handler before the size decision is final. The `413` is only applied afterwards by checking `c.error`. This lets the limit be bypassed when: • the handler does not read the body, • the handler reads only the first chunk(s) and returns, or • the handler reads the body but swallows the read error in `try/catch`. In all three cases the handler returns `200` before the limit check completes (or its result is observed). The fix is to enforce the size decision before `next()` runs, instead of retrofitting the response via `c.error` afterwards. Impact Applications relying on `bodyLimit()` as a hard boundary can be bypassed: oversized chunked requests can reach handler logic and return successful responses. Per-request data exposure is bounded by `maxSize`, but the documented guarantee — "oversized requests are rejected before business logic runs" — does not hold. Credits • @lalalala5678 (slow chunked / early return variants) • @Jvr2022 (error handling bypass)