← registry

FD-2026-012 Malformed JSON (trailing comma)

corruption trivial jsonparser

Anatomy

The classic hand-rolled serializer bug: a trailing comma before the closing brace. Java's Jackson, strict json.Unmarshal, and JSON.parse all reject it; JSON5 and Python's more forgiving setups may not. Whether your client's parser is strict IS the test.

Replay it

curl -i https://faultydata.com/r/FD-2026-012
// response appears here

Signature

{Status:200 Headers:map[] Body: Corrupt:malformed Delay:<nil> Flaky:<nil> Sequence:<nil> Drip:<nil> StallAfter:0 Hang:false Phases:[]}